IN  SCIENCE 

PATTEHSON 


STUDIES  IN  SCIENCE 

FOR 

SEVENTH  AND  EIGHTH  GRADES 

AND 

JUNIOR  HIGH  SCHOOLS 


ALICE  JEAN  PATTERSON,  B.S. 

TEACHER  OF  NATURE  STUDY  AND  ELEMENTARY  SCIENCE,  ILLINOIS  STATE 
NORMAL  UNIVERSITY,  NORMAL,  ILLINOIS 


»  *  Vo   o  e        ••»»'«•' 


CHICAGO  NEW  YORK 

ROW,  PETERSON  AND  COMPANY 


rs 


COPYRIGHT,  1919 
ROW,  PETERSON 
AND  COMPANY 


PREFACE 

This  book  is  designed  for  the  seventh  and  eighth  grades 
of  rural  and  village  schools,  and  for  the  first  book  in  science 
in  Junior  High  Schools.  Its  purpose  is  to  stimulate  interest 
in  the  simple  scientific  problems  found  in  daily  life,  to  train 
toward  a  correct  understanding  and  truthful  interpretation 
of  common  objects  and  phenomena,  and  to  arouse  some  ap- 
preciation of  the  intimate  relation  that  exists,  on  the  one 
hand,  between  science  and  health,  and,  on  the  other,  between 
science  and  economic  prosperity. 

The  work  has  grown  out  of  a  conscious  effort  to  fit  science 
study  to  the  needs  and  interests  of  grammar  school  children. 
All  the  exercises  have  been  used  in  regular  class  work  in  the 
training  school  of  the  Illinois  State  Normal  University.  They 
represent  much  sifting,  rejection,  and  rearrangement  during 
a  period  of  about  ten  years.  Most  of  them  have  had  the  addi- 
tional test  of  the  class-room  in  elementary  schools  where 
teachers  have  used  "Outline  Lessons  in  Nature-Study  Agri- 
culture," published  by  the  author  five  years  ago. 

The  material  is  chosen  from  the  immediate  environment 
of  the  pupils:  the  home,  school,  farm,  and  garden.  It  is 
sufficiently  agricultural  in  character  to  warrant  the  use  of 
the  book  as  a  text  in  elementary  agriculture.  While  some 
attention  has  been  given  to  continuity  of  subject-matter,  the 
chapters  in  the  main  are  arranged  with  reference  to  seasonal, 
rather  than  logical,  sequence;  biological  topics  occurring  in 
the  fall  and  spring,  physical  topics  in  the  winter. 

Part  One  deals  largely  with  the  habits,  structure,  and  uses 
of  domesticated  plants,  and  is  followed  during  the  winter  by 
a  study  of  soil  and  soil-water  in  their  relation  to  plant  growth. 
In  the  spring  a  number  of  practical  farm  and  garden  projects 
are  planned,  accompanied  by  definite  scientific  studies  that 
look  toward  some  realization  of  the  basic  principles  and  fun- 
damental laws  that  govern  plant  life. 

3 

413117 


4    "  PREFACE 

Part  Two  emphasizes,  in  its  biological  phases,  animal  life 
and  projects,  but  takes  up  also  some  of  the  lower  plant  forms, 
and  the  more  difficult  problems  of  plant  propagation.  The 
physical  studies  during  the  winter  are  based  upon  water  sup- 
ply, heating,  lighting  and  ventilating  the  home  and  school. 
In  the  spring,  simple  problems  of  landscape  gardening  are 
introduced. 

In  order  to  use  the  book  successfully,  teachers  should 
realize  that  pupils  must  have  a  hand-to-hand  contact  with 
real  objects  and  phenomena,  must  deal  with  actual  situations, 
must  come  naturally  to  one  problem  after  another.  The  les- 
sons aim  to  suggest  problems,  to  direct  observation,  investi- 
gation, and  experiment  along  lines  that  foster  openminded- 
ness,  promote  initiative,  and  lead  to  independent  effort  in 
the  discovery  of  truth.  The  discussions  and  explanations 
accompanying  each  study  are  designed  to  clear  up  doubts 
concerning  the  more  difficult  problems  and  to  state  facts  that 
may  not  be  found  at  first  hand. 

The  author  wishes  to  express  her  gratitude  to  the  teachers 
and  pupils  of  the  training  school  in  the  Illinois  State  Normal 
University  who  made  possible  the  practical  working  out  of 
these  studies  in  science.  Special  thanks  are  due  to  Mr.  Fred 
Ullrich,  Miss  Agnes  Storie,  and  Mr.  George  Cade,  for  their 
valuable  assistance  in  testing  various  phases  of  the  work,  and 
for  their  interest  and  advice  in  the  attempt  to  meet  the  needs 
of  the  boys  and  girls. 

The  author  wishes  also  to  acknowledge  her  indebtedness  to 
Miss  Ruby  Scott  for  her  careful  proof  reading,  to  Miss  Evalyn 
Clark,  Miss  Frances  Augustine,  and  Mr.  Harold  F.  James 
for  assisting  in  the  preparation  of  the  original  illustrations; 
and  to  those  publishers  who  have  permitted  the  use  of  their 
illustrations. 

ALICE  JEAN  PATTERSON. 


TABLE  OF  CONTENTS 


PART  ONE 


FALL  STUDIES 


PAGE 


Chapter               I     Plant  Studies 7 

Chapter             II     Farm  Crops 32 

Chapter           III     Weeds 67 

Chapter  IV     Tree  Studies 84 

WINTER  STUDIES 

Chapter             V     Soils 95 

Chapter           VI     Water  in  Soil 103 

Chapter          VII     Soil  Water  and  Plants 110 

Chapter       VIII     The  Work  of  Plants 120 

Chapter           IX     Food  and  Health 130 

SPRING  STUDIES 

Chapter             X  Garden  Studies  and  Home  Projects.  139 

Chapter           XI  Farm  Crops  and  Home  Projects. . .  176 

Chapter         XII     Trees   ; 189 

PART  TWO 

FALL  STUDIES  PAGE 

Chapter       XIII     Insects , 201 

Chapter        XIV     Fungi 228 

Chapter         XV    Yeast  and  Bacteria 239 

Chapter        XVI  Propagating  Plants  by  Cuttings. . .  255 

Chapter      XVII     Fruit  and  Fruit  Trees 265 

Chapter    XVIII     Domestic  Animals 283 


CONTENTS 


WINTER  STUDIES 


Chapter 
Chapter 
Chapter 
Chapter 
Chapter 
Chapter 


XIX 

XX 

XXI 

XXII 

XXIII 

XXIV 


SPRING  STUDIES 

Chapter  XXV 
Chapter  XXVI 
Chapter  XXVII 


Light  and  Lighting 325 

Water  Supply 339 

Forms  of  Water 354 

Heat  and  Heating 364 

Air 385 

Weather  .  .  406 


Poultry  and  Poultry  Projects 421 

Birds   436 

Landscape  Gardening 451 


Index 476 


STUDIES  IN  SCIENCE 

PART  ONE 

FALL  STUDIES 

CHAPTER  I 

PLANT  STUDIES 

Plants  are  among  the  most  important  objects  in  your 
environment.  They  not  only  add  much  to  the  beauty 
and  comfort  of  your  surroundings,  but  they  feed  and 
clothe  the  world.  Everything  that  you  eat,  if  you 
omit  water  and  certain  minerals  that  it  contains,  may 
be  traced  directly  or  indirectly  to  plants.  The  same 
thing  may  be  said  about  your  clothing.  Much  of  the 
raw  material  of  which  it  is  made  comes  directly  from 
plants,  while  the  rest  is  provided  by  animals  that  de- 
pend upon  plants  for  their  food. 

Plants  are  not  only  important  because  of  what  they 
directly  provide,  but  through  them  a  large  proportion 
of  the  men  and  women  all  over  the  world  earn  a  live- 
lihood. Some  of  you  are  even  now  directly  interested 
in  gardening  or  farming.  Your  garden  and  farm  pro- 

7 


g  STUDIES  IN  SCIENCE 

jects,  however,  will  not  have  their  full  educative  value 
unless,  along  with  the  practical  work,  you  study  the 
plants  themselves  to  find  out  all  you  can  about  their 
habits  of  growth,  their  relation  to  the  soil,  their  work 
and  their  uses. 

1.     VEGETABLES 

Material.  Vegetables  raised  in  the  district.  Spe- 
cial types — tomato,  squash  and  pumpkin,  potato  and 
sweet  potato. 

Study.  Make  a  list  of  all  the  different  kinds  of 
vegetables  that  have  been  grown  in  your  neighbor- 
hood this  season.  Classify  them  with  reference  to 
the  time  they  are  ready  for  use: 

1.  Spring. 

2.  Early  summer. 

3.  Late  summer. 

4.  Fall. 

Which  ones  continue  to  supply  food  for  the  long- 
est period  without  replanting?  Which  are  in  great- 
est demand  on  the  market!  Which  are  used  most 
frequently  on  your  home  table! 

The  tomato.  Observe  tomato  plants  and  note 
their  habit  of  growth.  What  is  the  position  of  the 
stems  of  an  unsupported  plant?  Describe  the  leaves. 
They  resemble  the  leaves  of  what  other  garden 


PLANT  STUDIES 


plants  ?  For  how  long  a  period  does  the  tomato  plant 
blossom  and  bear  fruit?  Look  for  all  stages  from 
the  unopened  flower  bud  to  the  mature  fruit. 


Fig.  1.  1.  A  tomato  flower  showing  the  slender  sepals  below  and 
the  six-pointed  corolla  with  the  stamens  clustered  at  the  center.  2. 
Flower  with  stamens  removed  showing  the  pistil  in  the  center.  The 
round  part  of  the  pistil  is  the  ovary.  3.  A  flower  from  which  the 
corolla  has  dropped.  The  withered  stamens  and  style  are  still  fas- 
tened to  the  growing  ovary. 

Examine  a  flower,  and  name  and  describe  its  parts. 
If  you  do  not  know  the  names,  find  them  in  Fig,  1. 
Compare  a  number  of  flowers  and  determine  in  what 
respects  they  vary.  What  parts  of  the  flowers  fade 
and  drop  off?  What  parts  remain  and  produce 
fruit! 

Make  cross-sections  of  several  green  tomatoes  and 
also  of  a  ripe  one.  How  many  seed  cells  or  sec- 
tions do  you  find!  Where  and  how  are  the  seeds 
fastened!  Compare  the  fruit  of  different  varieties 
as  to  the  amount  of  meat  and  seeds.  Look  for  dif- 
ferences among  individual  plants  of  the  same  va- 
riety as  to  the  number  and  size  of  the  tomatoes  and 


10  STUDIES  IN  SCIENCE 

the  quality  of  the  fruit.     Choose  for  seed  those  that 
have  the  characteristics  you  wish  to  reproduce  next ' 
year. 

Name  all  the  ways  that  tomatoes  are  used  for 
food.  How  are  they  preserved  for  future  use?  How 
important  are  they  as  an  industrial  plant? 

Discussion.  In  your  study  of  the  flowers  you 
probably  found  quite  a  difference  among  individuals 
in  the  number  of  se'  pals,  pet'  als  and  sta'  mens.  Some 
of  them  look  as  if  they  were  a  combination  of  sev- 
eral flowers.  This,  no  doubt,  has  come  about  by 
cultivation.  Botanists  tell  us  that  the  flower  of  the 
wild  plant  is  simple  and  that  the  fruit  does  not  have 
so  many  sections.  The  fruit  is  an  excellent  example 
of  a  berry.  It  is  the  ripened  6'  va  ry. 

Tomatoes  are  fast  becoming  important  industrial 
plants.  They  are  grown  in  almost  every  state  in 
the  union.  In  many  places  large  tracts  of  land  are 
given  over  to  their  culture.  They  are  canned  in 
large  quantities  in  canning  factories  as  well  as  by 
girls'  clubs  and  in  the  home.  Quantities  are  also 
used  every  year  in  factories  to  make  catsup,  pickles 
and  soup  preparations. 

History.  The  tomato  is  a  native  of  the  warm 
regions  of  South  America.  It  was  taken  to  Europe 
during  the  sixteenth  century,  but  was  not  used  for 
food  until  much  later.  In  United  States  it  was 


PLANT  STUDIES  H 

raised  as  a  curiosity  or  ornamental  plant  known  as 
the  "love  apple"  until  about  1830.  It  then  began 
to  be  used  on  the  table;  but  its  true  food  value  has 
been  recognized  only  about  fifty  years. 

Description.  The  stem  is  weak  and  when  unsup- 
ported trails  upon  the  ground.  You  probably  found 
flowers,  the  small  green  berry,  the  larger  one  and  the 
ripe  fruit  on  the  same  plant.  ''This  is  one  of  the  great 
advantages  of  the  tomato  plant,  since  it  continues  to 
blossom  and  bear  fruit  until  frost  kills  the  plant.  The 
leaves  are  compound,  and  they,  as  well  as  the  flow- 
ers, are  similar  to  those  of  the  potato.  These  plants 
both  belong  to  the  Nightshade  family. 

Canning  tomatoes.  If  you  have  never  canned  any 
fruit,  nothing  is  easier  to  begin  with  than  toma- 
toes. For  directions  see  Harvesting  and  Canning, 
page  150. 

THE  SQUASH  AND  OTHEE  CUCURBITS 

Material.  Growing  plants  of  squash,  pumpkin 
and  other  relatives  as  melons  and  cucumbers. 

Study.  No  garden  plant  has  more  interesting  char- 
acteristics and  habits  than  the  squash  and  its  relatives. 
Observe  one  of  the  growing  plants.  How  much  space 
does  it  occupy?  What  is  the  length  of  the  longest 
branch?  Look  down  upon  the  plant  and  determine 


12  STUDIES  IN  SCIENCE 

to  what  extent  the  leaves  hide  the  ground.  What 
special  adaptations  can  you  find  that  make  it  pos- 
sible for  all  the  leaves  to  be  exposed  to  the  light? 
Cut  a  stem  in  two  and  describe  its  structure.  What 
do  you  find  on  the  stem  besides  leaves!  Describe 
a  tendril.  Where  are  the  tendrils  attached!  What 
is  the  use  of  the  tendrils! 


Fig.  2.     Portion  of  a  squash  plant  showing  the  relation  of  leaves  and 

tendrils. 

Look  for  flowers.  How  many  kinds  do  you  find? 
Examine  the  two  kinds  carefully,  stating  how  they 
are  alike  and  how  different.  Try  to  make  out  the 
special  function  of  each  flower.  Observe  the  flowers 
in  the  evening.  What  do  they  do! 

What   insects   have  you  found  visiting  the   flow- 


PLANT  STUDIES  13 

ers?    Look  for  the  place  where  the  nectar  is  secreted. 

Cut  a  small  green  pumpkin  or  squash  across  the 
center.  How  many  distinct  sections  has  it?  To 
what  are  the  seeds  attached?  Cut  a  ripe  one  and 
note  the  changes  that  have  taken  place.  Compare 
a  section  of  a  cucumber  with  the  pumpkin  noting 
resemblances  and  differences. 

Discussion.  The  pumpkin,  squash,  cucumber,  melon 
and  gourd  belong  to  a  family  known  as  Cucurbitacae. 
They  are  often  called  cucurbits.  The  entire  family 
is  noted  for  the  wonderful  growth  that  the  plants 
make  in  a  few  weeks  or  months.  They  produce  not 
only  long  vines  and  large  leaves,  but  great  numbers 
of  large  fruit.  While  these  plants  have  the  habit  of 
trailing  upon  the  ground,  some  "of  them  are  good 
climbers.  The  gourd  is  an  example.  All  of  them 
have  tendrils  which  seems  to  indicate  that  perhaps 
some  time  in  their  past  history  they  were  all  good 
climbers.  Why  would  some  of  them  not  do  well 
as  climbers  now? 

History.  The  history  of  squashes  and  pumpkins 
is  interesting.  Botanists  believe  that  originally  they 
were  natives  of  Asia.  Nevertheless,  the  North  Amer- 
ican Indians  raised  them  in  their  fields  of  maize 
long  before  the  early  colonists  settled  in  America. 

You  will  find  it  worth  while  to  make  a  compara- 
tive study  of  any  other  cucurbits  that  may  be  found 


STUDIES  IN  SCIENCE 


in  your  neighborhood,  as  watermelons,  muskmelons 
and  cucumbers.  All  of  these  are  of  Asiatic  origin. 
They  were  first  brought  over  into  Europe  and  from 
there  to  America.  The  melons  thrive  best  in  the 
South  where  they  have  a  warm  soil  and  climate. 
Description.  You  found  two  kinds  of  flowers,  each 

with  a  five-lobed  yellow 
co  rol'  la  and  five  slen- 
der green  sepals.  The 
one  with  the  peculiar 
body  in  the  center  re- 
sembling a  yellow  can- 
dle is  a  stam'  i  nate 
flower.  If  you  rub  your 
finger  over  this  body, 
you  find  it  is  covered 
with  pol'  len.  It  is 
made  up  of  the  stamens. 
At  the  lower  part  of 
this  you  find  some  slits 
which  open  into  a  shal- 
low cup.  In  this  is  the 
nectar  which  attracts 
bees.  This  flower  is 
called  staminate  be- 
cause it  has  stamens 
and  no  pis'  til. 


Fig.  3.  1.  Staminate  flower  of  a 
squash.  A,  Corolla;  B,  One  sepal 
(Five  of  these  form  the  calyx);  2. 
Staminate  flower  with  corolla  and 
calyx  removed  to  show  the  stamens. 
A,  Opening  into  nectar  cup;  B,  Fila- 
ment; C,  Anthers  joined  to  form  a 
knob. 


PLANT  STUDIES 


15 


The  other  flower  with  the  ca'  lyx  and  corolla 
tened  to  the  top  of  a  green  body  which  later  be- 
comes the  fruit  is  the  pis'  til  late  flower.  Inside  the 
corolla  you  find  the  pistil  with  three  short  styles 
each  with  a  stig'  ma  at  the  top.  The  green  part  be- 
low is  the  ovary.  This  flower  also  has  a  nectar  cup 
situated  just  below  the 
styles..  Both  flowers  are 
necessary  to  produce  the 
seeds,  since  neither  has  all 
the  essential  organs. 

Bees  are  usually  the  car- 
riers of  pollen  from  the 
staminate  to  the  pistillate 
flowers.  As  the  bee  enters 
the  opening  to  get  nectar 
its  legs  and  body  become 
dusted  with  pollen.  When 
it  goes  to  a  pistillate  flower 
it  is  almost  certain  to  brush 
against  the  stigmas  and 
leave  some  pollen.  It  is  the 
pistillate  flower  that  always 
produces  the  fruit  and  seeds. 
In  the  cross-section  of  the  green  fruit  you  found 
three  curved  partitions  to  which  the  seeds  are  at- 
tached. Later  the  pulp  changes  to  stringy  coarse 


t 

Fig.  4.  1.  Pistillate  flower 
of  squash.  A,  Corolla;  B, 
Ovary  which  develops  into 
squash.  2.  Pistillate  flower 
with  corolla  removed  to  show 
pistil.  A,  Ovary;  B,  Nectar 
cup;  C,  Style;  D.  Stigma. 


16  STUDIES  IN  SCIENCE 

fibers  which  allow  the  ripe  seeds  to  drop  out  in  a 
mass. 

There  are  a  large  number  of  varieties  of  squash 
and  pumpkin. 

The  hard-shelled  squashes  and  a  few  pumpkins 
may  be  kept > fresh  for  winter  use  if  they  are  gath- 
ered before  being  frozen  and  stored  in  a  cool  place. 
They  may  be  successfully  canned  by  the  hot  water 
or  steam  process.  Besides  their  use  as  human  food, 
pumpkins  are  used  largely  as  food  for  cattle. 

Potatoes.  Are  potatoes  in  your  community  raised 
as  farm  or  garden  crops!  Are  they  early  or  late 
varieties?  At  what  time  are  they  ready  for  use? 
What  is  the  condition  of  the  plants  of  early  pota- 
toes at  this  season?  Of  late  potatoes? 

Study.  Examine  plants  that  are  still  green.  What 
is  the  position  of  the  stems?  Describe  the  leaves.  If 
there  are  any  flowers  find  their  parts.  If  they  have 
all  faded,  see  if  you  can  discover  where  they  were 
attached  to  the  stems.  Look  for  fruit.  How  do  you 
account  for  the  fact  that  potatoes  blossom  and  yet 
rarely  produce  fruit  and  seeds? 

Carefully  remove  the  soil  from  a  hill.  How  near 
the  surface  are  the  potatoes  or  tubers?  How  far 
from  the  center  of  the  hill?  Are  the  roots  above  or 
below  the  tubers?  How  are  the  tubers  fastened  to 
the  main  stem?  Dig  several  hills  and  compare  as 


PLANT  STUDIES  17 

to  the  number  of  tubers  and  uniformity  of  size. 
Which  hills  would  you  prefer  to  use  as  "seed  pota- 
toes "  next  year? 

If  possible,  compare  different  varieties  of  pota- 
toes and  note  differences  in  color,  shape,  smooth- 
ness of  skin,  number  and  depth  of  eyes.  Which 
do  you  consider  preferable  for  family  use?  Which 
may  be  peeled  with  the  least  waste?  Do  you  find 
scab,  rough  blotches,  on  any  of  the  potatoes?  What 
causes  scab? 

What  methods  of  harvesting  potatoes  are  em- 
ployed in  your  district?  Find,  if  possible,  what  the 
yield  is  per  acre.  What  is  a  good  average  yield? 
What  is  the  current  price  per  bushel?  What  do 
you  think  of  potatoes  as  a  paying  crop?  Which 
takes  the  greater  amount  of  labor,  the  raising  of 
a  crop  of  corn  or  a  crop  of  potatoes?  Which  yields 
the  greater  profit? 

Name  all  the  uses  of  potatoes  that  you  know;  all 
the  different  ways  of  cooking.  How  are  they  stored 
and  kept  for  future  use?  See  Home  Projects,  p.  159. 

Discussion.  The  potato  is  among  our  most  valu- 
able garden  and  farm  crops.  It  is  probably  used 
more  extensively  as  food  the  world  over  than  any 
other  crop  except  rice. ,  In  the  northern  states  it  is 
an  important  farm  crop;  in  most  other  states  it  is 
raised  as  a  truck  or  garden  crop. 


18  STUDIES  IN  SCIENCE 

History.  The  potato  is  a  native  of  America.  It 
was  probably  found  in  South  America  and  Mexico 
by  the  early  Spanish  explorers,  who  introduced  it 
into  Europe.  It  was  soon  grown  in  a  number  of 
the  European  countries.  It  became  so  important  a 
crop  in  Ireland  that  the  name  Irish  potato  was  given 
to  it.  The  early  colonists  from  Europe  brought  it 
over  into  Virginia  and  New  England.  It  has  been 
greatly  improved  by  cultivation  and  selection.  Great 
numbers  of  new  varieties  have  been  produced.  The 
wild  potato  is  still  found  in  Chili  and  Peru.  The 
tubers  of  this  wild  plant  are  very  small,,  not  larger 
than  small  marbles.  The  flowers  are  abundant  and 
most  of  them  produce  fruit  and  seeds. 

Description.  The  plant  is  weak  and  trailing,  a  rela- 
tive of  the  tomato,  which  it  resembles  in  leaves,  flow- 
ers and  fruit.  You  have  noticed  that  while  the  potato 
has  flowers  it  seldom  produces  fruit.  This  habit  is 
probably  brought  about  by  cultivation.  The  food 
the  plant  consumes  is  used  to  produce  large  tubers 
instead  of  fruit  and  seeds.  The  fruit  is  a  small 
green  ball  resembling  a  small  tomato. 

You  will  be  interested  to  know  that  seeds  are 
used  to  produce  new  varieties.  If  you  should  plant 
potato  seeds  you  would  get  a  large  number  of  dif- 
ferent kinds  of  potatoes.  Most  of  them  would  prob- 
ably be  of  little  value,  but  among  them  you  might 


PLANT  STUDIES  19 

find  one  of  such  excellent  qualities  that  it  would  be 
well  worth  growing.  You  could  give  it  a  name  and 
after  several  years  when  you  had  grown  a  large 
quantity  put  it  on  the  market  as  a  new  variety.  That 
is  just  what  potato  breeders  have  done  to  produce  the 
different  kinds  of  potatoes. 

Instead  of -seeds,  the  tuber  is  used  to  propagate 
new  plants.  Much  may  be  done  to  improve  the  po- 
tato crop  both  in  quantity  and  quality  by  a  careful 
selection  of  tubers  for  planting.  You  noticed  in 
comparing  the  hills  that  some  produce  a  larger 
number  of  fair-sized  potatoes  than  others.  These  are 
the  ones  that  should  be  chosen  to  plant  next  spring. 

Potatoes  are  used  chiefly  as  food  for  the  table. 
They  are  also  used  largely  in  some  places  for  mak- 
ing starch.  They  are  very  nutritious  when  prop- 
erly cooked.  Baked  potatoes  are  more  wholesome 
than  those  cooked  in  any  other  way.  Another  method 
is  to  boil  the  potatoes  with  the  skins  on.  In  both 
these  methods  certain  healthful  minerals  are  retained. 

Potatoes  yield  on  an  average  about  one  hundred 
bushels  per  acre.  Some  tracts  yield  two  or  three 
times  that  quantity.  The  estimated  cost  of  raising 
an  acre  of  potatoes  is  between  twenty-five  and  forty 
dollars.  You  can  easily  calculate  the  net  profit. 

Sweet  potatoes.  To  what  extent  are  sweet  pota- 
toes raised  in  vour  community?  What  is  the  habit 


20  STUDIES  IN  SCIENCE 

of  growth  of  the  plant?  How  many  branches  grow 
outward  from  one  plant?  What  is  the  length  of 
one  stem?  Describe  the  leaves.  Compare  a  num- 
ber of  leaves  and  note  variation  in  shape  of  blade 
and  lengtii  of  pet'  i  die. 

Study.  Dig  up  a  plant  and  observe  how  the  roots  are 
attached  to  the  stem.  How  many  potatoes  does  one 
plant  produce  1  Get  the  average  of  several  hills. 
How  greatly  do  the  potatoes  in  one  hill  vary  in  size? 
Compare  a  sweet  and  a  white  potato,  noting  dif- 
ferences. 

Look  for  flowers.  Where  are  they  attached  to  the 
vine?  Study  the  parts.  Find  the  seed  pods.  How 
many  sections  in  each?  How  many  seeds?  What 
common  flowering  plant  do  the  flowers,  leaves  and 
seeds  resemble? 

At  what  time  are  the  potatoes  harvested?  What 
is  the  yield?  How  valuable  is  the  crop?  What  is 
the  current  price  per  barrel  or  bushel?  How  are 
potatoes  stored  for  future  use?  What  is  the  history 
of  the  sweet  potato? 

Discussion.  The  sweet  potato  is  a  near  relative 
of  the  morning-glory.  You  probably  noticed  the 
similarity  in  the  shape  of  the  leaves.  The  flowers, 
too,  resemble  those  of  the  morning-glory.  However, 
in  the  North  flowers  are  rarely  produced.  In  the 
South  they  are  common.  They  are  purplish  pink 


PLANT  STUDIES  21 

in  color  and  the  corolla  is  from  one  to  two  inches 
across.  The  ovary  ripens  into  a  four-celled  pod 
very  much  like  that  of  the  morning-glory.  There 
is  one  seed  in  each  cell. 

History.  The  sweet  potato  stands  next  to  the  Irish 
potato  as  an  important  garden  crop  in  United  States. 
It  is  the  chief-  garden  crop  in  the  South.  Certain 
varieties  do  well  in  some  of  the  northern  states.  New 
Jersey  is  especially  noted  for  its  fine  sweet  potatoes. 

The  native  home  of  the  sweet  potato  is  not  definitely 
known,  but  botanists  believe  that  it  originated  in 
tropical  America.  It  reaches  its  highest  development 
there,  where  it  is  a  perennial,  living  year  after  year 
producing  its  roots  and  seeds  each  year. 

Description.  The  sweet  potato  is  a  fleshy  root, 
while  the  white  or  Irish  potato  is  a  tuber,  a  kind  of 
underground  stem.  Small  branch  roots  grow  from 
the  ends  and  sides  of  the  sweet  potato,  but  there  are 
no  eyes  or  buds  as  tkere  are  on  the  white  potato. 
The  fleshy  roots  are  used  to  propagate  the  plants. 
They  are  planted  early  in  the  season  in  a  hotbed. 
They  send  out  a  large  number  of  sprouts.  These 
are  pulled  off  and  set  about  eighteen  inches  apart 
in  ridges  that  have  been  prepared  for  them.  Some 
growers  set  out  a  few  plants  and  when  these  have 
grown  stems  eight  or  ten  inches  long  the  ends  are 
cut  off  and  set  out,  thus  producing  new  plants. 


22 


STUDIES  IN  SCIENCE 


2.     FLOWERING  PLANTS 

Material.    Flowering  plants  of  the  neighborhood. 

Choose  for  study  several  annuals  that  have  single 

flowers,    as    petunia,    nasturtium,    California    poppy, 

sweet  pea,  snapdragon  or  larkspur.     Note  the  habit 

of  growth,  the  characteristics 
of  the  stem  and  the  leaves. 
.  Study.  Examine  a  flower. 
What  different  organs  do  you 
find?  What  are  their  names! 
See  Fig.  5. 

What  is  the  function  of  a 
flower?  What  parts  are  neces- 
sary in  order  that  seeds  may  be 
formed?  Look  for  pollen  on 
the  anthers.  Where  must  the 
pollen  be  placed  in  order  to  be 
of  use  in  forming  seeds  ?  Find 
flowers  in  various  stages  of  de- 
velopment from  those  that  have 
just  opened  to  those  that  are  fading.  What  parts 
wither  and  drop  off?  What  ones  remain?  What 
develop  into  fruit  and  seeds!  Study  the  fruit  in  its 
stages  of  growth. 

What  insects  do  you  find  on  your  flowers?  Watch 
patiently  to  discover  what  they  are  doing.  Deter- 
mine, if  possible,  where  the  nectar  is  secreted  and 


Fig.  5.  Section  of  a 
petunia  flower.  In  the  cen- 
ter is  the  pistil.  A,  Ovary; 
B,  Style;  C,  Stigma  (at 
the  sides  are  the  five 
stamens)  ;  D,  Filament;  E, 
Anther,  in  which  pollen  is 
produced. 


PLANT  STUDIES  23 

to  what  extent  insects  must  become  dusted  with  pollen 
in  order  to  obtain  it. 

The  following  outline  will  be  found  helpful  in  the  study  of  flow- 
ering plants. 

1.  Name: 

2.  Habit  of  growth: — erect,  procumbent,  climbing,  creeping. 

3.  Stem: — tall,  low,  branching,  spreading,  smooth,  hairy,  sticky, 
etc. 

4.  Leaves: — simple,  compound,   large,  small,  hairy,  soft,   rough, 
special  characteristics  that  make  them  attractive. 

5.  Flower: — a.     single,  cluster;     b.     dates  of  flowering;     c.     sim- 
ple description  of  parts;     d.     special  features.    Where  is  the  nectar 
secreted?    Insects  that  visit  the  flower. 

6.  Fruit: — a.     kinds;    pod,    capsule,    berry,    pappus    flyer,    etc.; 
b.     seeds: — few,  many,  large,  small,  special  adaptions  for  distribu- 
tion. 

7.  Remarks: — history,  family  relationship,  value  for  ornamental 
purposes. 

Filled  out  for  the  petunia,  the  outline  will  appear  in  your  note- 
books as  follows: 

1.  Name:     Petunia. 

2.  Habit  of  growth: — procumbent  and  spreading  with  many  erect 
branches. 

3.  Stem: — hairy  and  sticky. 

4.  Leaves: — simple,  vary  in  size,  hairy,  sticky,  thick. 

5.  Flower: — a.     simple;     b.     dates  of  flowering,  from  June  until 
frost;     c.     calyx,  green,  five  sepals;  corolla,  white,  purple,  or  pink, 
funnel  shape,  long  tube;   stamens,  five  fastened  to  the  tube  of  the 
corolla;  pistil,  one  in  center  with  large  green  ovary,  slender  style 
and   disk-like  stigma;      d.     nectar  is  secreted  at  the  base  of  the 
corolla  tube.     Moths  and  butterflies  visit  the  flowers  to  get  nectar. 
All  parts  of  the  flower  wither  and  fall  off  except  the  calyx  and  ovary. 

6.  Fruit: — a.     formed  from  ovary,  a  conical  pod  or  capsul.     b. 
seeds,  many  and  small;  pod  splits  at  top  and  seeds  fall  out. 

7.  History,  etc.:     The  petunia  that  we  know  has  been  produced 
by  the  mixing  of  two  species  that  are  natives  of  South  America. 
One  of  these  had  a  large  white  flower,  the  other  a  small,  reddish 
purple  one.     The  two   species  were   introduced  into  Europe  some 


24  STUDIES  IN  SCIENCE 

time  between  1823  and  1832,  and  it  is  from  the  mixing  of  these  that 
we  get  the  different  colors  that  petunias  show  today. 

The  petunia  belongs  to  the  Nightshade  family;  hence  is  a  relative 
of  tomatoes  and  potatoes. 

In  a  similar  way  fill  out  the  outline  for  other  flowering  plants. 
You  will  find  some  interesting  differences  among  them.  For  ex- 
ample, the  nasturtium  has  its  nectar  secreted  in  a  long  spur  which 
is  formed  from  three  of  the  sepals.  It  has  very  prominent  streaks 
on  the  petals  which  lead  do\vn  to  the  nectar.  These  are  called 
nectar  guides. 

The  California  poppy  has  its  sepals  in  the  form  of  a  green  cap 
which  encloses  the  flower  bud.  This  cap  falls  off  when  the  flower 
opens  and  nothing  is  left  but  the  little  frill  to  which  it  was  fas- 
tened. 

The  sweet  pea  has  three  differently  shaped  petals  in  each  flower. 
It  is  known  to  botanists  as  the  butterfly  flower.  Each  kind  of  petal 
has  a  name;  the  broad  one  at  the  top  is  the  banner,  the  side  ones 
are  the  wings,  and  the  two  that  are  joined  together  to  hold  the 
stamens  and  the  pistil  form  the  keel.  Our  common  beans  and  peas, 
the  different  kinds  of  clover,  locust  and  red  bud  trees  all  have  this 
same  kind  of  flower.  The  fruit  also  is  similar,  a  flat  pod  with  seeds 
on  the  inside.  The  pod  is  called  a  legume. 

Composite  flowers.  After  you  have  studied  several 
simple  flowers,  choose  one  that  has  a  large  number 
of  small  flowers  crowded  together  into  a  head,  such  as 
a  sunflower,  cosmos  or  gaillardia. 

Examine  a  sunflower  or  other  head.  How  many 
different  kinds  of  flowers  do  you  find?  How  do  the 
little  flowers,  or  florets,  in  the  center  differ  from  those 
at  the  outside?  Choose  for  close  observation  one  of 
the  florets  that  has  two  thread-like  bodies  projecting 
from  the  top  and  ending  in  a  curl.  Find  all  the  parts 
of  the  flower.  How  many  points  has  the  brownish 


PLANT  STUDIES  25 

corolla!  How  many  sides  has  the  brown  tube  at  the 
center.  Open  up  the  tube  with  a  pin  and  see  what  is 
on  the  inside.  What  are  the  two  curled  over  threads 
at  the  top?  To  get  the  names  study  Fig.  7.  What 
part  will  produce  the  seed!  Break  a  head  through 
the  center  so  that  you  may  better  see  the  arrange- 
ment of  the  florets.  Describe  the  little  bodies  that 
you  see  sticking  up  at  the  base  of  each  little  flower. 

Which  florets  open  first!  If  possible  watch  a  head 
for  a  number  of  days  to  solve  this  problem.  Examine 
closely  one  of  the  outside  flowers.  What  parts  does 
it  lack?  Does  it  produce  seed? 

Study  a  head  that  has  gone  to  seed.  What  parts 
of  the  florets  are  left!  Count  the  seeds.  What 
use  is  made  of  sunflower  seeds?  How  valuable  are 
they! 

Discussion.  The  sunflower  is  an  excellent  type  of 
a  large  group  of  flowering  plants  both  wild  and  cul- 
tivated that  have  a  great  number  of  small  flowers 
crowded  into  a  head.  All  such  plants  belong  to  the 
family  Compositae.  We  usually  speak  of  the  flowers 
as  composites. 

Look  for  other  composites  among  your  flowering 
plants.  You  will  find  some  interesting  differences 
among  them.  The  zinnia  and  asters  have  well  devel- 
oped styles  and  stigmas  in  their  ray  flowers,  so  they 
produce  seeds  as  well  as  the  disk  flowers.  The  bracts 


STUDIES  IN  SCIENCE 


in  these  flowers  are  fringy  and  colored  and  add  no 

little  beauty  to  the  flowering  head. 

Make  a  collection  of  all  the  composites  among  your 

cultivated  flowers. 

Sunflowers    are    of    considerable    value    in    certain 

states,  especially 
Kansas,  Nebraska 
and  parts  of  Mis- 
souri. The  stalks  are 
sometimes  used  for 
fuel,  while  the  seeds 
are  used  to  feed  stock 
and  poultry.  A  very 


Fig.  6.  1.  Ray  flowers  of  a  zinnia 
showing  the  curled  stigmas,  the  style, 
ovary,  and  one  petal  in  the  corolla. 
2.  A  disk  flower  of  the  zinnia  showing 
the  five-lobed  corolla  attached  to  the 
ovary,  and  the  slender  bract  at  one  side. 


good  oil  resembling 
olive  oil  is  made  from 
the  seeds.  An  acre  of  sunflowers  yields  about  sixty 
bushels  of  seed. 

Description.  The  sunflower  is  a  good  specimen 
to  study  because  its  parts  are  so  large.  The  outside 
florets  with  the  showy  petals  are  known  as  ray  flow- 
ers, while  the  small  inner  ones  are  disk  flowers.  The 
disk  flowers  have  all  the  organs  present,  the  two 
parted  calyx,  the  five  pointed  corolla,  the  stamens 
enclosed  in  a  tube  and  the  pistil  whose  style  grows 
up  through  the  midst  of  the  stamen  tube  with  the 
two  curled  stigmas  at  the  top.  The  ovary  is  at  the 
very  lowest  part.  The  small  leaflike  bodies  that  you 


PLANT  STUDIES 


27 


B... 


Fig.  7.  1.  A  disk  flower  of 
the  sunflower  in  the  early  stage 
of  blossoming.  2.  The  same 
flower  in  a  later  stage.  A, 
Ovary;  B,  Calyx;  C,  Corolla;  D, 
Anther  tube;  E,  Stigma. 


find  attached  near  the  base  of  the  florets  are  bracts. 
The  same  name  is  given  to  the  over-lapping  green 
bodies  that  are  attached  to  the  underside  of  the  head. 
This  entire  group  of  bracts 
is  called  the  involucre.  It 
protects  the  head  before  it 
is  ready  to  open  up  its 
flowers. 

You  probably  discovered 
that  the  ray  flowers  do 
not  have  either  stamens  or 
stigmas;  hence  they  do  not 
produce  seeds.  They  are 
the  showy  flowers,  how- 
ever, and  probably  aid  in  attracting  the  insect  visitors 
that  transfer  pollen  from  one  flower  to  another. 

The  regular  arrangement  of  the  flowers  and  later 
of  the  seeds  in  the  head  is  one  of  the  interesting- 
features  of  the  sunflowrer.  The  florets  open  from  the 
outside  toward  the  center,  so  you  can  find  in  the 
same  head  all  the  stages  from  those  that  are  begin- 
ning to  wither  at  the  outside  to  the  unopened  buds 
in  the  center. 

Perennials.  Look  among  your  perennial  flowers 
for  composites.  Make  a  list  of  all  the  perennials 
that  blossom  in  the  fall.  What  parts  of  these  plants 
live  over  winter?  Why  are  they  called  perennials! 


28  STUDIES  IN  SCIENCE 

Perennials  may  be  used  even  more  than  annuals  to 
make  your  home  grounds  attractive.  By  making 
careful  selection  you  may  have  perennials  flowering 
from  early  spring  until  heavy  freezes  in  the  northern 
states  and  all  the  year  around  in  the  southern  states, 

3.     WILD  FLOWEKS 

Study.  What  wild  flowers  are  in  blossom  now? 
Where  do  you  find  them?  What  different  colors  do 
you  find  among  them?  Are  they  annuals  or  peren- 
nials? Look  at  a  number  to  determine  whether  they 
have  simple  or  composite  flowers. 

Make  a  detailed  study  of  golden-rods.  Use  the 
outline  suggested  for  annual  flowering  plants.  Both 
golden-rods  and  asters  are  composites.  The  heads 
of  the  golden -rod  are  very  small  and  are  arranged 
together  at  the  top  of  the  branches,  thus  giving  the 
beautiful  feathery  appearance  to  the  cluster.  You 
will  find  that  they  have  both  disk  and  ray  flowers. 
Small  as  the  flowers  are  you  can  see  that  both  kinds 
produce  seeds. 

Watch  the  changes  that  take  place  as  the  flowers 
fade.  What  is  the  color  of  the  heads  when  all  have 
gone  to  seed?  What  gives  them  their  fluffy,  feathery 
appearance?  What  adaptation  have  they  for  scatter- 
ing their  seeds?  Look  for  different  species  of  golden- 


PLANT  STUDIES  29 

rod.  Make  a  detailed  study  of  asters  and  other  wild 
flowers.  If  you  cannot  go  to  the  fields  to  watch  the 
changes  that  take  place  in  these  flowers,  place  a  few 
sprays  of  each  in  jars  of  water  indoors.  They  will 
continue  their  development  here.  Another  reason 
for  doing  this  is  that  golden-rods  and  asters  are 
almost  as  beautiful  after  the  flowers  have  faded,  with 
their  gray,  fluffy  seed  heads,  as  they  are  when  in  full 
bloom.  Even  after  the  seeds  with  their  hairy  para- 
chutes have  flown  away,  these  plants  are  still  attract- 
ive with  their  dark  brown  stems  and  silvery  white 
disks.  In  order  to  appreciate  the  beauty  of  the  land- 
scape during  the  fall  and  winter,  these  should  be 
observed  in  the  fields  and  along  roadsides  with  other 
plants. 

A  few  of  these  wild  plants  mixed  in  with  your 
perennial  border  in  the  garden  will  add  much  to  its 
attractiveness.  You  can  grow  them  either  from  seeds 
or  roots. 

Discussion.  While  you  are  studying  flowers  both 
annual  and  perennial  observe  carefully  the  different 
shades  and  colors  and  determine  which  ones  look 
well  growing  side  by  side.  You  can  plan  color 
schemes  for  flower  projects  much  easier  in  the  fall 
and  summer  when  you  see  the  flowers  themselves, 
than  you  can  in  the  spring  when  you  have  nothing 
but  seed  catalogues  to  depend  upon. 


•JO  STUDIES  IN  SCIENCE 

While  you  grow  your  flowering  plants  in  order  to 
derive  pleasure  from  their  beauty,  it  is  well  to  re- 
member that,  as  far  as  the  plants  themselves  are 
concerned,  their  flowers  exist  not  for  us  but  to  pro- 
duce seeds.  Scientists  tell  us,  although  it  has  not 
been  proved  conclusively,  that  the  bright  colors  of 
flowers  help  to  bring  insects  to  them. 

It  is  certain,  of  course,  that  the  nectar  is  secreted 
to  attract  insects.  All  this  is  done  so  that  pollen  may 
be  transferred  from  the  anthers  to  the  stigmas.  The 
stamens,  which  produce  the  pollen,  and  the  pistils  are 
the  essential  organs  of  the  flower.  When  you  study 
botany  you  will  learn  in  detail  about  the  wonderful 
process  that  takes  place  in  the  making  of  a  seed. 
The  following  paragraphs  give  only  a  brief  discus- 
sion of  this  process. 

The  making  of  a  seed.  The  first  step  is  the  trans- 
fer of  pollen  from  an  anther  to  a  stigma.  This  is 
called  pollination.  The  transfer  of  pollen  from  an 
anther  to  a  stigma  of  the  same  flower  is  self-pollina- 
tion. Cross-pollination  is  the  transfer  of  pollen  from 
the  anther  of  one  flower  to  the  stigma  of  another 
flower  of  the  same  species. 

The  pollen  is  formed  in  the  anther  and  when  it  is 
ripe  the  anther  bursts  open  and  it  comes  to  the  out- 
side. The  stigma  is  the  part  of  the  pistil  that  is 
prepared  to  receive  the  pollen.  When  it  is  ripe  or 


PLANT  STUDIES  31 

ready  for  the  pollen  it  lias  a  sticky  secretion  on  it, 
so  that  if  a  grain  of  pollen  falls  upon  it  or  is  brushed 
from  the  hairs  of  an  insect  it  holds  this  fast.  The 
little  grain  then  germinates  and  produces  a  tube- 
like  structure  called  the  pollen-tube.  This  grows 
downward  through  the  style  to  the  ovary. 

In  the  pollen-tube  two  cells  are  found,  called  sperm- 
cells.  In  the  ovary  is  an  egg-cell.  When  the  tube 
reaches  the -ovary  one  of  the  sperm-cells  unites  with 
the  egg-cell  and  forms  a  new  cell.  This  union  is 
known  as  fertilization. 

The  new  cell  is  the  beginning  of  the  seed.  It  grows 
rapidly  for  a  time,  then  stops  growth,  becomes  dry, 
and  we  say  the  seed  is  ripe.  When  you  find  a  great 
number  of  seeds  in  a  pod  it  means  that  there  was  a 
pollen  grain  and  an  egg-cell  for  every  seed  that  was 
formed. 

Bees,  moths  and  some  wasps  aid  plants  by  carry- 
ing pollen  from  one  flower  to  another  and  thus  help 
to  insure  the  production  of  seed. 


CHAPTER   II 

FARM  CROPS 

> 

1.       COKN 

Material.  A  cornfield  in  the  community;  an  entire 
corn  plant  including  the  root  system.  This  should 
be  removed  from  the  ground  while  the  leaves  are  still 
green.  If  it  is  kept  in  the  basement  of  the  school- 
room or  other  cool  place,  it  will  dry  slowly  and  may 
be  used  for  study  any  time  during  the  year.  Provide 
also  a  number  of  ears  of  different  varieties  of  corn 
including  several  small,  unripe  ears.  These  should 
be  removed  from  the  stem  when  two  or  three  inches 
in  length.  They  may  be  preserved  indefinitely  in  a 
jar  of  alcohol  or  four  per  cent  formalin. 

Field  study.  Select  a  plot  ten  hills  square  either 
in  your  own  plot  or  in  a  portion  of  a  large  cornfield. 
What  is  the  distance  between  the  rows?  Between 
the  hills?  How  many  stalks  in  a  complete  hill?  How 
many  hills  with  one  stalk?  With  two?  How  many 
missing  hills?  What  is  the  actual  number  of  stalks 
in  the  plot?  What  would  be  the  number  if  each  hill 
had  three  stalks?  What  percentage  of  a  perfect 

32 


FARM  CROPS 


33 


stand  does  the  plot  show  ?  How  many  stalks  have  one 
good  ear?  Two!  How  many  stalks  are  barren? 
How  many  with  smut?  With  suckers?  (A  sucker  is 
a  small  stalk  branching  from  the  main  stem  close 
to  the  ground.  It  never  bears  a  good  ear,  and  there- 
fore uses  up  food  with  little  profit.) 

How  much  greater  would  your  yield  be  if  you  had 
a  perfect  stand  with  one  good  ear  on  each  stalk? 

THE  COKN  PLANT 

Roots.     Notice  the   root   system.     How  many   dis- 
tinct kinds   do  you  find?     Describe   the  main   roots 


MI  m 


Fig. 


Eoot  system  of  a  corn  plant. 


as  to  number,  size  and  branching.  What  is  their 
direction  of  growth?  If  you  have  access  to  a  corn- 
field, dig  carefully  around  a  plant  to  find  the  rela- 


STUDIES  IN  SCIENCE 


tion  of  the  roots  to  the  soil.  How  near  the  surface 
are  they!  How  deep  do  they  grow!  How  far  out 
from  the  hills  ?  How  far  between  the  rows ! 

Where  are  the  brace  roots!     How  many  joints  on 
the  stem  produce  these  roots!    Examine  a  number  of 

plants  and 
report  on 
the  greatest 

number  of  joints  bearing  brace 
roots.  Do  they  all  succeed  in 
reaching  the  ground!  What  is 
the  function  of  these  roots! 

Stem.     What  is  the  height  of 
the   stem!     To   what  extent   do 
plants  vary  in  height !  How  thick 
is  the  stem!    Measure  it  near  the 
base  and  again  just  below  the  tas- 
sel. What  is  the  difference  f  How 
many   joints,    or   nodes,    in    one 
stem!     Where  are   they  closest 
together!       What     is     the     ad- 
vantage of  this  ! 
With  a  sharp  knife  cut  a  stem  into  small  sections. 
How  many  different  structures  do  you  find  in  a  cross- 
section!    Describe  them.    Make  a  longitudinal  section 
and  describe  what  you  find. 

Leaves,     Count  the  leaves  on  one  plant.     Where 


V 

Fig.  9.  A  shoot 
si  J  owing  a  row  of 
pistillate  flowers.  A, 
Ovary;  B,  Style. 


FARM  CROPS  35 

are  the  longest  ones?  The  shortest!  Where  and 
how  are  they  fastened  to  the  stem?  What  are  the 
parts  of  one  leaf?  The  lower  part  that  wraps 
around  the  stem  is  called  the  sheath.  The  long 
slender  part  is  the  blade.  Is  the  sheath  open 
or  closed?  What  part  of  the  blade  is  longer,  the 
middle  or  the  margin?  What  advantage  do  you  see 
in  this  wavy  margin?  Examine  the  plant  where  it 
is  hinged  to  the  sheath  and  describe  what  you  see. 
What  is  the  chief  work  of  the  leaves? 

Flowers.  What  do  you  find  at  the  top  of  the 
stalk?  Do  you  know  what  the  tassels  really  are?  De- 
scribe them.  Which  do  they  resemble  more,  heads  of 
wheat  or  of  oats?  Carefully  remove  the  husks  from 
a  very  small  ear,  one  that  has  just  started  to  grow. 
Trace  the  silk  down  to  the  cob.  What  do  you  find 
here?  See  Fig.  9. 

Ear.  Where  is  the  ear  attached  to  the  stalk?  How 
long  is  the  shank  or  stem?  Remove  the  husks.  To 
what  are  they  attached?  Compare  the  outer  with 
the  inner  ones.  What  do  you  find  on  the  outer  ones 
that  leads  you  to  believe  that  husks  are  modified 
leaves?  In  what  condition  do  you  find  the  silks  on 
a  mature  ear?  How  many  rows  of  kernels  are  there 
on  one  ear?  Count  them  on  several  and  get  the 
average.  Is  the  number  odd  or  even?  How  do  ker- 
nels at  the  tip  and  butt  differ  from  those  on  the  other 


36 


STUDIES  IN  SCIENCE 


parts  of  the  ear?     What  is  the  number  in  one  row? 

If  you  discard  the  small  kernels  at  the  tip  and  butt 

how   many   will   one   ear  furnish   if   used   for   seed? 

How  many  hills  will  it  plant  if  you  use  three  grains 

in  each  hill? 

Selection.  In  se- 
lecting seed,  con- 
sider the  entire 
plant  as  well  as  the 
ear.  Visit  a  corn- 
field and  select 
plants  from  which 
to  choose  seed. 
Look  for  the  fol- 
lowing points:  1. 
An  erect,  strong, 
well  formed  stalk 
growing  in  a  hill 
with  two  others.  2-. 
Well  developed 
brace  roots.  3.  A 
plant  free  from 
smut  and  suckers. 
4.  The  ear  situated 
a  little  above  the 
middle  point  of  the 
stalk. 


Fig.  10.  A,  A  well  shaped  and  well  filled 
ear;  B,  A  perfect  tip;  C,  Kernels  well  filled 
to  the  tips,  wedge  shape  so  that  no  space 
is  lost;  D,  A  well  filled  butt. 


FARM  CROPS  37 

In  choosing  seed  corn  the  chief  object  that  a  farmer 
has  is  the  yielding  qualities. 

Examine  a  number  of  ears  and  determine  what 
characteristics  they  have  that  will  make  them  pro- 
duce a  good  yield  next  year.  You  will  no  doubt  have 
the  following  points: 

1.  Shape:     An  ear   that   is  cylindrical  will  have  more  kernels 
than  one  that  tapers  too  much  at  the  tip. 

2.  Size:      (a)     length,     (b)     circumference.      An    ear    of    good 
length  and  width  will,  of  course,  yield  more  corn  than  a  smaller  ear. 

3.  Rows:     The  rows  should  be  close  together  so  there  will  be 
no  waste  space. 

4.  Tips  and  butts  should  be  well  filled  out. 

5.  Shape    of    kernels:       (a)      Wedge-shaped    grains    have    little 
space  between  the  tips  at  the  cob;     (b)     a  deep  grain. 

These  are  the  chief  characteristics  that  make  an  excellent  yielding 
ear.  There  are  twro  other  points,  however,  that  must  be  given  con- 
sideration. 

6.  The  ear  must  be  well  matured,  not  soft  and  flabby. 

7.  The  color  of  the  ear  should  be  true  to  the  special  variety  of 
corn.     There  should  be  no  mixing  of  colors  or  grains;   white  corn 
should  have  a  white  cob,  yellow  corn  a  red  one. 

If  you  were  arranging  a  sample  of  ten  ears  for  a 
corn  contest  according  to  these  seven  points,  you 
should  have  the  ten  ears  as  uniform  as  possible  in 
shape,  size,  color,  etc. 

Value.  How  valuable  is  the  corn  crop  in  your 
neighborhood?  What  is  the  average  yield?  The  cur- 
rent price  per  bushel!  Look  in  your  geography  to 
determine  how  corn  ranks  among  grains  raised  in 
United  States.  What  states  are  included  in  the  "Corn 
Belt"? 


38  STUDIES  IN  SCIENCE 

Uses.  Write  a  list  of  all  the  uses  of  corn  that  you 
know.  Make  a  collection  of  com  products.  Put  them 
into  small  bottles  or  vials  and  mount  on  stiff  card- 
board. Make  a  collection  also  of  as  many  different 
species  and  varieties  of  corn  as  possible. 

Discussion.  No  doubt  you  have  discovered  in  your 
study  of  the  corn  plant  that  it  resembles  grass  in 
some  of  its  characteristics.  In  fact,  it  belongs  to  the 
Grass  family.  It  has  fibrous  roots  which  grow  in  all 
directions  frequently  reaching  at  maturity  a  depth 
of  from  three  to  four  feet.  The  brace  roots  help  to 
hold  the  corn  erect. 

Stem.  The  cross-section  of  the  stem  showed  the 
outside  woody  part  which  gives  it  strength,  and  the 
white  pith  on  the  inside  with  the  threadlike  fibers 
scattered  through  it.  These  are  called  fibro-vascular 
bundles.  They  are  really  little  systems  of  canals 
which  carry  water  and  other  raw  material  from  the 
roots  to  the  leaves,  and  digested  food  from  the  leaves 
back  to  the  stem,  roots,  seeds,  or  wherever  ft  may 
be  needed. 

Leaves.  The  chief  work  of  the  leaves  is  to  manu- 
facture food  for  the  entire  plant.  You  have  already 
observed  that  the  leaf  surface  on  one  plant  is  very 
great.  This  makes  possible  the  manufacture  of  vast 
quantities  of  food  so  that  growth  may  be  very  rapid. 
The  wavy  margin  prevents  the  long  leaves  from  being 


FARM  CROPS 


39 


torn  in  the  wind.  The  projection  that  you  found 
at  the  hinge  between  the  blade  and  the  sheathe  is 
called  the  rain  guard.  This  keeps  the  water  during 
rains  from  pouring  down  between  the  sheathe  and 
stem.  Moisture  here  would  probably  result  in  the 
growth  of  mold  or  mildew. 

Flowers.  The  tassels  and  small  shoots  with  the 
silks  are  the  corn  flowers.  -They  do  not  have  all  the 
parts  of  ordinary  flowers,  but 
they  do  have  the  essential 
parts.  If  you  have  ever  seen 
a  corn  plant  just  after  the  tas- 
sels have  opened,  you  have 
noticed  the  yellow  powder  or 
pollen  scattered  upon  the 
leaves  and  even  on  the  ground. 
If  you  looked  at  the  tassel 
closely  you  saw  the  stamens 
that  produced  the  pollen 
dangling  from  each  of  the  little 
side  branches,  the  spikelets. 
Since  the  little  flowers  of 
the  tassel  produce  only  the 
stamens,  they  are  the  stami- 
nate  flowers.  The  tiny  shoot 
that  becomes  the  ear  has  rows 
of  round  bodies  each  with  ,  a 


Fig.  11.  1.  The  pistil- 
late flower  of  corn.  A, 
The  glumes  that  produce 
the  chaff  when  the  corn  is 
ripe;  B,  The  ovary  which 
produces  the  kernel;  C, 
The  style  or  silk;  D,  The 
stigma.  2.  The  stigma  en- 
larged to  show  the  hairs 
that  catch  the  pollen. 


40 


STUDIES  IN  SCIENCE 


silk  fastened  to  it.  These  are-  pistils.  The  round 
body  is  the  ovary  and  the  silk  is  the  style.  This 
is  the  pistillate  flower  because  it  bears  pistils  and 
no  -stamens.  Both  kinds  of  flowers  are  necessary  to 
produce  the  seed. 

Germination.  First  pollination  takes  place ;  that  is, 
a  grain  of  pollen  settles  upon  the  stigma,  which  is  the 
end  of  the  silk.  If  the  pollen  comes  from  the  tassel 
of  the  same  plant,  wo  say  the  flower  is  self-pollinated 

If  it  comes  from  another 
plant  the  flower  is  cross- 
pollinated.  Most  corn  in 
our  fields  is  cross-polli- 
nated. The  wind,  which  is 
the  chief  carrier,  trans- 
fers the  pollen  from  one 
plant  to  another. 

The  pollen  grain  on  the 
silk  germinates  and  forms 
the  pollen  tube,  which  grows  downward  through  the 
entire  silk  until  it  reaches  the  ovary.  In  it  are  two 
sperm  cells,  so  small  that  you  would  have  to  have  a 
microscope  of  high  power  to  see  them.  When  the 
cells  reach  the  ovary,  it  is  ready  to  receive  them.  In 
fact,  it.  has  been  getting  ready  for  them  while  the 
tube  has  been  growing  through  the  silk.  In  it  are 
two  important  cells  also.  One  of  these  is  called  the 


Fig,   12. 
corn.     A. 


Staminate   flovrcr  of 
The  stamens  as  they 


hang  to  shed  the  pollen;  B.  The 
leaf-like  glumes. 


FARM  CROPS  41 

egg-cell,  and  the  other  the  en'  do  sperm  cell.  One  of 
the  sperm-cells  from  the  pollen  tube  unites  with  the 
egg-cell  to  form  a  new  cell.  This  has  the  power  to 
grow  until  it  forms  a  little  plantlet  which  we  call  the 
germ  or  em'  bry  6  part  of  the  corn  grain.  The  union 
of  this  sperm-cell  with  the  egg-cell  in  the  ovary  is 
called  fertilization.  This  must  always  occur  before 
the  germ  or  embryo  can  be  formed. 

The  second  pollen  tube  cell  unites  with  the  endo- 
sperm cell  of  the  ovary  and  the  resulting  new  cell 
grows  into  the  large  starchy  part  of  the  corn  kernel, 
which  is  called  the  endosperm.  This  is  simply  a  store- 
house of  food  placed  around  the  little  germ  to  supply 
it  with  nourishment  while  it  is  developing  its  first 
roots  and  leaves.  It  is  because  of  the  fact  that  plants 
in  this  and  similar  ways  store  so  much  nourishment 
in  their  seeds  to  furnish  food  for  the  little  embryo 
that  seeds  are  so  valuable  as  food  for  men  and 
animals. 

As  the  seed  germinates  and  grows  the  endosperm 
is  used  up.  By  the  end  of  the  season  it  has  disap- 
peared; but  the  embryo  grows  into  a  new  plant.  Just 
what  kind  of  plant  it  will  be  and  what  kind  of  corn 
it  will  produce  depend  largely  upon  the  character  of 
the  plants  that  produced  the  pollen  grain  and  the 
ovary  cell  that  united  to  form  the  beginning  of  the 
seed.  You  can  easily  see  from  this  why  the  charac- 


42 


STUDIES  IN  SCIENCE 


teristics  of  both  plants  are  so  important  and  why  corn 
growers  should  select  for  seed  ears  as  nearly  perfect 
as  possible,  grown  upon  plants  of  the  kind  they  wish 
to  produce.  If  it  is  desired,  a  detailed  study  of  the 
grain  may  be  made  at  this  time  instead  of  in  the 
spring.  See  Fig.  30. 

Selecting  and  storing  seed.  The  best  time  to  se- 
lect seed  corn  is  early  in  the  fall  before  heavy  frosts, 
and  the  best  place  is  in  the  field,  not  in  the  crib.  You 


Fig.  13.     Seed  corn  rack. 

have  already  discovered  the  important  characteristics 
to  consider  in  choosing  corn  for  seed.  After  the  seed 
is  selected  comes  the  question  of  storing  it  for  the 
winter.  Certain  conditions  are  essential  for  keeping 
the  seed  corn: 


FARM  CROPS  43 

1.  The  atmosphere  should  be  dry. 

2.  The   temperature   should  be  even  and  not  too 
cold. 

3.  The  ventilation  should  be  good. 

A  simple  method  is  to  tie  a  number  of  ears  together 
and  hang  them  up  in  some  convenient  place  such  as 
an  attic,  dry  shed,  or  an  unused  room.  Agricultural 
colleges  have  suggested  a  number  of  methods.  See 
Fig.  13. 

Uses  of  corn.  Corn  is  used  most  extensively  as 
food  for  stock.  Not  only  is  the  grain  used,  but  also 
the  stem  and  leaves  as  green  or  dry  fodder,  the  whole 
plant  in  silage,  the  bran  in  ground  feed,  and  the  germs 
in  corn-oil  ca^e. 

Corn  also  furnishes  a  large  supply  of  human  food 
in  the  form  of  corn-meal,  breakfast  foods,  hominy, 
corn  starch,  syrup  and  oils. 

Corn  oil  is  manufactured  into  rubber  from  which 
boots,  shoes,  tires,  linoleums  and  oilcloth  are  made. 
It  is  used  also  in  the  manufacture  of  soap  and  in  the 
mixing  of  paints.  The  cellulose  from  the  stem  is 
used  to  a  slight  degree  in  the  manufacture  of  paper. 
The  cobs  are  used  in  the  manufacture  of  pipes  and 
also  for  fuel.  Even  the  stalks  are  used  for  fuel  in 
some  of  the  western  states. 

History.  Corn  is  a  native  of  the  New  World.  The 
Indians  called  it  maize.  Its  original  home  was  prob- 


44 


STUDIES  IN  SCIENCE 


ably  in  Mexico  or  South  America.  When  America 
was  settled  by  the  colonists,  corn  had  already  been 
domesticated  by  the  Indians,  who  taught  the  white 
man  how  to  grow  it. 

Types.  There  are  six  important  species  of  maize.* 
The  most  valuable  variety  is  Dent,  which  is  our  com- 
mon field  corn.  It  gets  its  name  from  the  dent  in  the 


THE    SEVEN   SPECIES   OF  CORN 


•7r 


M 


Fig.  14.     Seven  species  of  corn. 

crown  of  the  grain.  There  are  many  varieties  of  Dent 
corn  including  all  the  white  and  yellow  as  well  as  the 
red  and  mixed  colors. 

Flint  corn  has  a  smaller  ear  than  Dent,  with  from 
eight  to  twelve  rows  of  kernels.  The  grains  are 
smooth  and  hard.  This  corn  is  used  largely  as  fod- 
der and  silage.  It  is  the  chief  corn  grown  in  the 

northern  tier  of  states. 

*A  new  type,  the  branch  corn,  has  been  developed,  but  as  yet  has 
no  commercial  significance. 


FARM  CROPS  45 

Sweet  corns  are  known  by  their  wrinkled  grains 
and  their  large  percentage  of  sugar.  As  green  corn 
they  are  used  largely  for  human  food.  It  is  said  that 
the  first  sweet  corn  cultivated  in  America  was  secured 
from  the  Susquehanna  Indians  in  1779. 

Pop  corn  is  characterized  by  its  small  grains  and 
its  power  to  turn  wrong  side  out  when  heated.  When 
corn  pops,  the  moisture  in  the  grain  vaporizes  and 
expands.  It  is  held  in  by  the  hard  covering  which 
at  last  explodes. 

Pod  corn  is  rarely  seen.  It  is  raised  chiefly  as  a 
curiosity.  Each  grain  is  enclosed  in  a  little  husk  or 
pod  of  its  own.  The  entire  ear  is  also  inclosed  in 
husks.  This  is  of  interest  because  it  is  supposed  to 
be  the  original  type  of  corn  from  which  all  the  others 
have  sprung. 

Soft  varieties  of  corn  are  raised  only  in  southern 
regions.  The  mummy  corn  of  Chile  and  Peru  is  said 
to  belong  to  this  group. 

2.     WHEAT* 

Material.  Specimens  of  entire  wheat  plants,  sam- 
ples of  grains,  collection  of  wheat  products,  plates  or 
boxes  for  germination  tests. 

*Note.  Wheat  and  other  farm  crops  that  provide  food  or  clothing 
may  be  studied  with  profit  either  in  the  city  or  country.  While  the 
lessons  are  suggested  for  the  fall,  they  may  be  used  equally  well 
in  the  spring  in  regions  where  spring  wheat  is  grown.  Since  in 


46  STUDIES  IN  SCIENCE 

Study.  Make  a  list  of  the  different  foods  that  are 
made  from  wheat.  Look  at  labels  on  boxes  of  cereals  or 
breakfast  foods,  macaroni,  etc.  What  different  kinds 
of  wheat  flour  do  you  know!  How  do  breads  made 
from  these  differ?  Begin  at  once  to  make  a  collec- 
tion of  wheat  products.  Place  them  in  small  vials, 
label  and  fasten  by  means  of  fine  wire  to  a  sheet  of 
stiff  cardboard.  A  chart  showing  heads  and  grains 
of  different  varieties  of  wheat  will  also  be  of  interest. 

The  wheat  plant.  Examine  a  wheat  plant.  -De- 
scribe the  roots.  How  tall  is  the  stem?  Break  it 
and  describe  the  inside.  How  are  the  leaves  fastened 
to  the  stem!  How  many  distinct  parts  to  each  leaf? 

The  head.  We  call  this  kind  of  flowering  head  a 
spike.  Each  of  the  branches  is  a  spikelet.  How  many 
spikelets  in  a  spike?  Count  the  number  in  each  head 
and  get  the  average.  How  many  divisions  in  one 
spikelet?  How  many  grains?  If  you  have  more  than 
one  variety  of  wheat  compare  them  as  to  the  number 
of  spikelets  and  grains.  Estimate -the  whole  number 
of  grains  in  one  head.  Carefully  pull  to  pieces  what 
is  left  of  the  flower  inclosing  the  grain.  Each  small 

many  places  the  study  of  the  plant  must  be  made  at  a  time  when 
field  study  is  impossible,  every  school  should  have  as  a  part  of  its 
equipment  a  number  of  specimens  of  entire  wheat  plants.  They 
may  be  kept  from  year  to  year  by  tying  them  into  small  bundles 
and  hanging  them  up.  It  will  add  to  the  profit  of  the  study  if  sev- 
eral varieties  are  used.  There  should  be  at  least  one  specimen  of 
bearded  and  one  of  beardless  wheat. 


FARM  CROPS  47 

leaflike  body  is  a  glume.  If  the  wheat  is  a  bearded 
variety,  note  to  what  the  beard  or  awn  is  attached. 

The  grain.  Examine  a  grain  and  write  down 
everything  that  you  see.  Determine  which  end  of 
the  grain  was  fastened  to  the  stem.  How  deep  is  the 
crease  in  the  grain?  Compare  dry  grains  with  those 
that  have  been  soaked  over  night,  noting  differences. 
Split  open  a  dry  grain.  What  do  you  find  on  the 
inside?  Open  a  soaked  grain  and  compare  with  the 
dry  one.  What  part  of  the  grain  is  used  in  making 
pure  wheat  flour?  Whole  wheat  flour?  Bran?  What 
part  produces  the  new  plant? 

Purity  test.  Spread  a  small  handful  of  wheat  on 
a  piece  of  white  paper.  Now  separate  the  weed  seeds 
and  other  foreign  objects  from  the  grain.  Put  the 
wheat  in  one  pile  and  the  foreign  matter  in  another. 
Estimate  about  what  proportion  is  pure  seed.  If  you 
have  a  pair  of  balances,  weigh  each  and  get  exact 
per  cent  of  purity.  If  you  find  weed  seeds,  deter- 
mine if  possible  what  kind  they  are.  This  is  a  good 
time  to  refer  to  your  weed  list,  which  you  will  find 
on  page  77. 

Germination  test.  If  you  are  planning  to  sow 
wheat,  you  should  make  a  germination  test.  To  do 
this,  take  one  hundred  grains  from  a  sample  of  seed 
wheat.  Place  moist  sand  or  soil  in  a  dinner  plate 
or  shallow  box.  Scatter  the  seeds  on  the  surface  of 


48  STUDIES  IN  SCIENCE 

the  sand  not  allowing  any  two  to  touch  each  other. 
With  your  finger  gently  press  each  grain  so  that  it 
will  rest  firmly  in  the  sand,  but  do  not  cover  it.  Turn 
another  plate  over  this  one  to  keep  the  moisture  in. 
Set  it  away  in  a  warm  place. 

Watch  for  the  germination  of  the  seeds.  How 
long  after  the  planting  before  the  first  small  sprouts 
appear!  Watch  them  from  day  to  day  until  you 
are  certain  that  no  more  grains  will  sprout.  By 
counting  the  grains  that  have  sprouted,  you  will 
be  able  to  determine  at  once  the  per  cent  of  germi- 
nation. If  you  sowed  only  the  usual  quantity  per 
acre,  what  percentage  of  a  perfect  stand  would  you 
expect  to  get  from  the  tested  seed! 

Study.  Examine  one  of  the  sprouted  grains.  From 
what  part  do  the  roots  grow!  How  many  roots 
are  there?  Where  does  the  shoot  appear!  Which 
grows  more  rapidly  at  first,  the  roots  or  the  shoot? 

Plant  some  wheat  in  a  box,  keep  it  moist  and  watch 
the  growth  of  the  plants.  If  you  have  a  school  gar- 
den or  a  small  plot  on  the  school  grounds  that  may 
be  used,  plant  some  out-of-doors  and  watch  it  at  inter- 
vals all  fall  and  winter.  What  change  takes  place 
in  the  habit  of  growth  when  it  is  about  six  weeks 
old?  What  advantage  is  it  to  the  plant  to  spread 
out  rather  than  to  grow  erect?  To  what  extent  do 
the  plants  remain  green  over  winter?  Explain  why 


FARM  CROPS  49 

a  vast  amount  of  snow  is  a  benefit  to  the  wheat  crop. 

What  enemies  has  wheat?  How  may  they  be  com- 
bated? The  Hessian  fly  and  the  chinch  bug  are  among 
the  worst  insect  foes.  Eust  and  smut  are  common 
fungous  diseases. 

Discussion.  From  your  observation  you  find  three 
distinct  parts  to  each  grain  of  wheat;  the  covering, 
or  hull  from  which  bran  is  made,  the  starch  which 
constitutes  most  of  the  white  flour,  and  the  small 
dark  body,  the  embryo.  The  embryo  is  the  little  plant 
that  develops  its  root  and  shoot  when  the  seed  is 
kept  sufficiently  warm  and  moist.  The  starch  fur- 
nishes food  for  the  growing  plant.  In  whole-wheat 
flour  the  embryo  and  the  inner  covering  of  the  grain 
are  used  as  well  as  the  starch.  Graham  flour  is  a 
mixture  of  finely  ground  bran  and  ordinary  flour. 

Varieties  of  wheat.  "Wheats  are  divided  into  spring 
and  winter  varieties.  Winter  wheats  are  planted 
in  the  fall  and  live  through  the  winter  beginning  their 
growth  again  in  the  spring.  Spring  wheat,  as  the 
name  indicates,  is  planted  in  the  early  spring  and 
matures  its  grain  the  first  season. 

There  are  hard  and  soft  varieties  of  both  spring 
and  winter  wheat.  Winter  wheats  are  preferred  in 
all  regions  where  the  extremes  of  temperature  are 
not  too  severe  for  them,  because  they  yield  more 
than  spring  wheats.  They  are  ready  to  harvest  ear- 


50  STUDIES  IN  SCIENCE 

Her,  and  are  better  able  to  withstand  attacks  of 
insects  and  fungous  diseases.  Almost  two-thirds  of 
all  the  wheat  grown  in  the  United  States  is  winter 
wheat. 

Kansas  and  Nebraska  are  the  centers  for  the  hard 
winter  wheat;  the  middle  western  states  raise  semi- 
hard  wheat;  while  the  southern  states  raise  both 
semi-hard  and  soft.  The  great  wheat  regions  of  the 
North,  Minnesota  and  the  Dakotas,  raise  hard  spring 
wheat. 

There  are  a  great  many  different  varieties  of  all 
these  kinds  of  wheat.  You  may  be  interested  to 
know  how  new  varieties  are  obtained.  There  are  two 
ways.  Perhaps  some  of  you  have  noticed  in  walking 
through  a  wheat  field  that  here  and  there  a  few 
heads  seem  somewhat  different  from  the  rest.  Wheat 
is  likely  to  have  "sports,"  or  variations.  That  is 
why  these  plants  differ  from  others  though  grown 
from  apparently  the  same  kind  of  seed.  Breeders 
who  wish  to  obtain  new  varieties  select  one  of  these 
heads  that  seems  to  have  good  characteristics.  They 
save  the  seeds  and  plant  them  in  a  small  plot  by 
themselves.  If  during  the  first  year  the  good  char- 
acteristics seem  to  persist,  (he  seed  from  this  small 
plot  is  preserved  and  planted  on  a  larger  plot.  In 
a  few  years  there  is  enough  seed  to  plant  a  number 
of  acres.  If  the  variety  proves  valuable,  the  breeder 


FARM  CROPS  51 

gives  it  a  special  name,  and  a  new  variety  of  wheat 
is  soon  on  the  market.  This  is  called  the  "selection 
method.77 

A  second  method  is  by  means  of  "cross  pollina- 
tion.7' Wheat  does  not  cross  pollinate  naturally  as 
corn  does.  This  is  because  the  flower  is  so  arranged 
that  the  pollen  does  not  escape  but  falls  upon  the 
pistil  of  the  same  flower.  If  breeders  wish  to  cross 
pollinate  wheat,  they  must  do  it  by  hand.  This  is 
a  kind  of  work  that  requires  special  training  and  must 
be  done  by  experts.  The  stamens  of  one  flower  are 
carefully  removed  and  on  the  pistil  of  this  flower 
pollen  from  the  flower  of  a  different  variety  is  placed. 
In  this  way  characteristics  of  the  two  plants  are 
mingled  in  the  new  seeds  that  are  formed,  and  a 
new  variety  may  be  produced. 

Planting  wheat.  What  methods  of  planting  or 
sowing  wheat  are  employed  in  your  district!  If 
possible  visit  a  farm  and  examine  a  drill  and  a  broad- 
cast seeder.  The  drill  plants  the  wheat  in  rows  about 
eight  inches  apart.  The  seeder  scatters  it  broad- 
cast over  the  field.  In  the  early  days  farmers  sowed 
wheat  broadcast  by  hand. 

Value  of  the  wheat  crop.  How  many  farmers  in 
your  district  raise  wheat?  What  is  the  average  yield 
per  acre!  What  is  the  price  per  bushel?  How  im- 
portant is  the  wheat  crop  in  United  States?  About 


52  STUDIES  IN  SCIENCE 

one-fifth  of  all  the  wheat  raised  in  the  world  is  pro- 
duced in  United  States.  This  amounts  annually  to 
something  over  700,000,000  bushels.  With  the  help 
of  your  geography  locate  the  wheat  regions  of  our 
country  to  find  out  what  large  cities  owe  their  pros- 
perity to  the  manufacture  of  wheat  into  flour  and 
other  products.  Besides  the  grain  the  straw  is  of 
value  as  food  for  cattle  and  horses.  The  yield  of 
wheat  varies  greatly  in  different  localities.  Some 
fields  yield  as  low  as  fifteen  bushels  per  acre.  Others 
yield  fifty  and  sixty. 

Wheat  project.  If  you  live  in  a  region  where  wheat 
is  an  important  crop,  you  may  be  interested  in  start- 
ing a  plot  of  your  own.  Follow  the  directions  for 

planting  oats,  page  183. 

/ 

3.     GKASSES  AND  LEGUMES 

Material.  Grasses  and  clovers  found  in  the  com- 
munity, specimens  showing  roots,  collections  of  leaves, 
flowers,  and  seed  heads,  for  study  and  booklets. 

Study.  Name  all  the  different  places  in  your 
neighborhood  where  grasses  of  some  kind  are  grow- 
ing. To  what  extent  do  you  find  roadsides,  vacant 
lots  and  railroad  right-of-ways  covered  with  grasses? 

Meadow  grasses.  What  grasses  do  you  find  in 
meadows?  Does  one  grass  constitute  the  entire 


FARM  CROPS  53 

meadow  or  is  there  a  mixture  of  plants!  Examine  a 
timothy  plant.  What  is  its  habit  of  growth?  Does 
it  grow  in  chimps  or  spread  evenly  over  the  ground! 
Dig  down  to  the  roots.  Describe  them.  How  deep 
do  they  go!  Describe  the  leaves;  the  flowering  head. 
Which  does  it  resemble  more,  a  head  of  wheat  or  one 
of  oats!  What  is  timothy  used  for!  When  is  it  har- 
vested! How  is  it  kept  for  future  use!  What  other 
meadow  grasses  are  grown  in  the  community!  Com- 
pare them  with  timothy  noting  resemblances  and 
differences.  If  timothy  is  not  grown  in  the  region 
where  you  live,  choose  your  chief  meadow  grass  and 
study  it  using  the  topics  suggested  for  timothy. 

Pasture  grass.  What  is  the  chief  pasture  grass 
in  your  district!  Study  the  habits  of  growth,  espe- 
cially the  underground  parts.  See  outline  for  blue- 
grass,  page  452.  What  characteristics  make  a  good 
pasture  grass!  Are  timothy  and  blue-grass  peren- 
nials or  annuals!  What  annual  grasses  are  grown 
in  your  neighborhood!  For  what  purposes  are  they 
used! 

Wliat  is  the  value  of  timothy  hay  per  ton!  What 
is  the  average  yield  in  tons  per  acre! 

Clovers.  How  many  kinds  of  clover  grow  in  your 
district!  Examine  a  red  clover  plant.  How  many 
stems  do  you  find  in  the  loose  rosette!  Where  do 
you  find  the  youngest  shoots!  What  is  the  advan- 


54  STUDIES  IN  SCIENCE 

tage  to  the  plant  of  growing  close  to  the  ground? 
Describe  the  leaves.  Look  at  the  leaflets  after  sun- 
set; what  change  in  position  do  they  take!  Study 
the  flowers.  Decide  whether  the  clover  head  is  a 
single  flower  or  a  cluster.  How  many  flowers  in  one 
head!  Which  open  first,  those  at  the  lower  or  upper 
portion  of  the  head!  Look  closely  at  one  small 
flower.  What  common  garden  flower  does  it  resem- 
ble! Where  is  the  nectar  secreted!  What  insects 
are  commonly  found  feeding  upon  it!  Find  a  with- 
ered head  and  look  for  the  seeds.  How  many  seeds 
does  each  small  flower  produce!  What  shape  are 
the  seeds! 

Dig  up  a  clover  plant.  If  the  soil  is  very  hard 
and  dry,  water  it  thoroughly  the  preceding  day. 
Describe  the  root.  What  is  the  advantage  of  its 
great  length  and  thickness!  Which  remains  green 
longer  during  a  summer  drought,  clover  or  grasses! 
Why!  Look  carefully  on  the  roots  for  small  round- 
ish bodies  about  the  size  of  pin  heads.  These  are 
called  tubercles  or  nodules.  On  what  part  of  the 
root  are  they  most  numerous!  Count  the  nodules 
on  one  small  root.  What  are  these  nodules  and  why 
are  they  on  the  roots! 

How  many  crops  of  clover  are  harvested  in  one 
season!  Which  crop  usually  produces  seed!  What 
is  the  price  of  the  seed!  How  valuable  is  clover 


FARM  CROPS  55 

hay?     For  what   other  purpose   than   to   feed   stock 
is  clover  grown?     When  and  how  is  it  planted? 

Find  other  clovers  and  compare  with  red  clover  as 
to  habit  of  growth  and  uses.  How  does  white  clover 
spread?  Why  is  it  a  better  pasture  than  meadow 
grass?  What  characteristics  have  all  clovers  in 
common  ? 


Fig.  15.     Harvesting  alfalfa. 

Sweet  clover.  Make  a  study  of  sweet  clover  using 
the  above  topics.  Which  does  it  resemble  more,  red 
clover  or  alfalfa?  How  many  of  the  farmers  in  your 
district  raise  sweet  clover?  What  is  the  length  of 
life  of  a  sweet  clover  plant? 

Alfalfa.  Describe  an  alfalfa  plant.  How  many 
main  stems  has  it?  Does  it  grow  more  or  less  erect, 
than  red  clover?  Compare  the  leaves  with  those 
of  clover  noting  resemblances  and  differences.  How 
do  the  flowers  differ  from  those  of  clover?  In  what 


56  STUDIES  IN  SCIENCE 

are  they  similar?  What  kind  of  a  root  has  it!  Look 
for  nodules.  To  what  extent  is  alfalfa  raised  in  your 
community!  How  many  crops  does  it  produce  in 
one  season!  How  does  it  compare  with  clover  as  a 
forage  crop! 

Soy-beans  and  cow-peas.  If  these  plants  are  grown 
in  your  district,  study  them  noting  how  they  grow 
and  what  kind  of  leaves,  fruit  and  seeds  they  have. 
Determine  whether  or  not  the  roots  have  nodules. 
What  use  is  made  of  these  plants! 

Discussion.  Grasses  and  legumes  are  important 
forage  crops  providing  a  large  per  cent  of  the  food 
of  domestic  animals.  They  are  classified  with  ref- 
erence to  methods  of  feeding  into  meadow,  pasture, 
and  soiling  crops.  In  pastures  animals  help  them- 
selves to  the  growing  plants.  Meadows  are  cut,  the 
plants  air  dried  or  cured,  and  stored  as  hay  for  future 
use.  Soiling  crops  are  cut  green  and  immediately 
fed  to  the  animals. 

Blue-grass  is  the  most  important  pasture  grass  in 
the  northern  states.  Frequently  white  clover  is  mixed 
with  it.  In  the  southern  states  Bermuda  is  the  chief 
pasture  grass.  The  characteristics  that  make  these 
desirable  pasture  plants  are:  1.  They  form  a  thick 
sod  that  stands  trampling  and  crowds  out  weeds. 

2.  They  have   fine   blades   that   stock   like   to   eat. 

3.  They  are  hardy  and  able  to  endure  extremes  of 


FARM  CROPS  57 

cold  or  drought.  The  first  and  third  characteristics 
are  due  to  their  method  of  spreading  by  the  under- 
ground stem  or  rootstock. 

Timothy  is  the  chief  meadow  grass.  Redtop,  mea- 
dow fescue  and  orchard  grass  are  used  in  some  reg- 
ions where  timothy  does  not  thrive  well.  In  many 
localities  a  mixture  of  red  or  alsike  clover  with 
timothy  is  used.  Sudan  grass,  a  very  tall  productive 
variety,  is  coming  into  use  in  a  number  of  states. 

All  of  the  grasses  we  have  discussed  are  peren- 
nials. Some  farmers  raise  millets,  which  are  annual 
grasses,  and  use  them  for  hay  or  pasture.  Perennial 
plants  are  those  which  grow  year  after  year.  An- 
nuals grow  for  just  one  year. 

You  found  that  all  the  grasses  have  certain  char- 
acteristics in  common:  1.  Long,  narrow,  parallel- 
veined  leaves.  2.  Numerous  small  fibrous  roots. 
3.  Jointed  stems.  You  found  two  kinds  of  flowering 
heads  represented  by  timothy  and  blue-grass.  The 
timothy  head  is  a  spike;  blue-grass,  a  panicle.  All 
of  our  small  grains,  as  well  as  corn,  sorghum  and 
kaffir  corn,  belong  to  the  Grass  family. 

Legumes.  The  clovers,  alfalfa,  cow-peas  and  soy- 
beans belong  to  the  Legumenosae  family,  but  they  are 
commonly  called  legumes.  They  get  the  name  from 
the  flat  pod  in  which  the  seeds  are  borne,  which  is 
characteristic  of  most  of  the  family.  Such  a  pod  is 


58  STUDIES  IN  SCIENCE 

called  a  legume.  Our  garden  beans  and  peas  are 
good  types  of  legumes.  You  probably  discovered 
the  similarity  between  the  flowers  of  clovers  and 
those  of  peas  and  beans. 

Legumes  are  excellent  forage  plants  containing 
more  nutritious  foods  than  grasses.  This  is  espe- 
cially true  of  alfalfa  and  red.  clover.  Alfalfa  is  raised 
more  in  the  western  states;  clover  in  the  states  east 
of  the  Missouri  river.  However,  the  acreage  of  alfalfa 
is  increasing  year  by  year.  Sweet  clover  is  begin- 
ning to  find  a  place  as  a  forage  crop.  Many  farmers 
in  the  Middle  West  are  growing  it  instead  of  alfalfa. 

Eed  clover  produces  two  crops  each  year.  The 
first  is  harvested  for  hay;  the  second  usually  for 
seed.  In  the  West  alfalfa  is  cut  from  six  to  ten  times 
in  one  season.  In  the  Mississippi  Valley  and  adja- 
cent states  it  is  possible  most  seasons  to  secure  three 
cuttings.  Sweet  clover  also  yields  three  cuttings. 
It  must  be  harvested  when  young  before  the  stems 
become  woody. 

Soy-beans  and  cow-peas  are  frequently  used  as 
soiling  crops,  but  in  the  South  they  are  harvested 
for  hay.  They  are  annuals.  Alfalfa  and  red  and 
white  clover  are  perennials ;  sweet  clover  is  a  biennial. 

In  addition  to  their  value  as  food  for  animals, 
legumes  are  important  plants  to  aid  in  maintaining 
soil  fertility.  They  do  this  in  three  ways: 


FARM  CROPS  59 

1.  They  furnish  a  large  amount  of  decaying  roots, 
stems,  and  leaves  that  enrich  the  soil. 

2.  Their  long  thick  roots  which  penetrate  the  soil 
so  deeply  aid  in  making  it  porous  and  in  giving  both 
air  and  water  a  better  opportunity  to  reach  the  roots. 

3.  They  supply  the  soil  with  nitrogen,  an  element 
that  all  seed  plants  must  have  in  order  to  live  and 
grow. 

You  found  nodules  on  the  roots  of  clovers  and  other 
legumes.  These  are  growths  caused  by  small  living 
organisms  called  bacteria.  (One  is  a  bacterium.) 
The  bacteria,  which  are  either  on  the  seed  or  in  the 
soil,  attach  themselves  to  the  young  clover  roots. 
The  tissues  of  the  roots  grow  around  them  forming 
the  small  nodules.  In  these  the  bacteria  live  and  mul- 
tiply very  rapidly.  They  take  free  nitrogen  from  the 
air  in  the  soil  spaces  and  change  it  into  a  form  that 
clover  can  use,  for,  although  there  is  plenty  of  free 
nitrogen  in  the  air  surrounding  clover  and  other 
plants,  they  cannot  use  it  in  that  form. 

All  the  legumes  have  the  bacteria  nodules  on  their 
roots.  They  are  not  only  supplied  with  all  the  nitro- 
gen they  need,  but  their  leaves,  stems  and  roots  are 
all  well  stocked  with  it.  If  the  plants  are  plowed 
under,  the  nitrogen,  which  is  now  in  the  form  of  a 
compound  called  a  nitrate,  goes  into  the  soil  and  fur- 
nishes a  supply  for  other  crops  that  are  grown  here. 


60  STUDIES  IN  SCIENCE 

Nitrogen  is  frequently  lacking  in  soils  that  are  con- 
stantly used  for  crops,  so  you  can  realize  how  impor- 
tant it  is  to  grow  legumes  in  order  to  keep  a  suffi- 
cient supply  of  nitrogen  in  the  soil. 

4.     COTTON 

Material.  An  entire  cotton  plant,  some  ripe  bolls, 
pictures  of  cotton  gins  and  cotton  factories,  collec- 
tion of  cotton  products. 

The  cotton  plant.  Study  a  cotton  plant  either  in 
the  field  where  it  is  growing  or  have  one  in  the  school 
room.  How  high  does  the  plant  grow!  Examine. the 
root  and  describe  it.  How  deep  in  the  ground  does 
it  extend!  Describe  the  stem.  How  close  to  the 
ground  does  it  begin  to  branch!  Count  the  number 
of  large  branches.  Break  or  cut  a  stem  at  the  largest 
part.  What  parts  can  you  find  in  the  cross-section! 
How  does  the  structure  differ  from  that  of  the  corn 
stem! 

Describe  a  leaf.  Compare  leaves  found  on  differ- 
ent parts  of  the  plant.  "What  is  the  greatest  number 
of  lobes  that  you  find  in  one  leaf!  The  fewest! 
What  is  the  most  common  number!  Which  have 
the  greatest  number,  those  on  the  upper  or  lower 
branches!  How  are  the  leaves  arranged  with  ref- 
erence to  each  other,  opposite  or  alternate!  Look 
on  the  under  side  of  a  leaf  for  a  little  hollow  spot 


FARM  CROPS  61 

near  the  base  of  the  midrib.  What  is  in  this  depres- 
sion or  pit!  How  many  such  pits  can  you  find  on 
one  leaf!  Taste  the  liquid. 

The  flower.  Examine  a  flower.  What  do  you  find 
at  the  lower  part!  How  many  fringed  bracts  are 
there!  Describe  them.  Pull  them  back  till  you  can 
see  the  cuplike  calyx  with  five  or  six  notches  at  the 
top.  What  color  is  it!  How  many  petals  are  there! 
What  different  colors  do  you  find!  Look  at  flowers 
of  different  ages  to  see  if  you  can  account  for  the 
different  colors.  What  insects  have  you  seen  around 
the  flowers!  What  do  you  find  in  the  center  of  the 
flower!  You  find  a  great  number  of  stamens  all 
grown  together  to  form  a  large  tube.  Remove  the 
stamen  tube.  In  an  old  flower  it  will  come  off  easily 
leaving  the  pistil  which  is  in  the  center  of  the  flower. 
Find  the  large  green  ovary  at  the  base  of  the  pistil. 
Note  the  slender  style  and  the  stigma  at  the  top. 
How  many  division  lines  has  the  ovary!  Find  flow- 
ers that  are  withering,  and  those  from  which  the 
withered  parts  have  dropped.  Determine  what  part 
of  the  flower  develops  into  the  fruit  or  boll.  What 
other  parts  of  the  flower  remain  attached  to  the  boll! 

The  seeds.  Cut  open  lengthwise  an  ovary  from 
which  the  dried  corolla  and  stamens  have  just  fallen. 
Note  position  of  the  rudimentary  seeds.  Cut  open 
another  that  is  about  an  inch  long  and  note  the  white 


62  STUDIES  IN  SCIENCE 

silvery  substance  growing  around  the  seeds.  Cut 
open  one  that  is  still  larger  to  find  that  the  white 
substance  is  forming  into  threadlike  fibers.  Study 
a  ripe  boll.  Where  does  it  open!  How  many  sections 
has  it!  Remove  the  fibers  from  the  seeds.  Where  are 
they  attached!  How  many  seeds  in  one  section! 
In  one  boll!  Count  a  number  to  find  variations. 
Straighten  out  the  fibers  on  one  seed.  How  long  are 
they!  Twist  some  of  them  together  and  note  their 
strength. 

Remove  the  cotton  films  from  around  the  seeds 
and  examine  the  seeds.  Take  off  the  hull  and  study 
the  kernel.  Crush  some  of  the  kernels  on  a  piece  of 
paper.  What  do  you  find? 

Discussion,  From  an  economic  standpoint  cotton 
is  one  of  the  most  important  crops  that  we  have  in 
the  United  States.  You  found  that  the  plant  grows 
from  three  to  six  feet  in  height.  It  has  a  large  tap- 
root that  sends  out  a  number  of  branches.  These 
grow  to  quite  a  depth  and  anchor  the  plant  firmly  in 
the  soil.  The  stem  resembles  that  of  a  shrub  or  tree 
with  a  brownish  bark.  Inside  the  bark  is  a  strong 
layer  of  wood  and  in  the  middle  is  the  pith.  The 
stem  is  unusually  strong  and  woody  for  an  annual. 
In  fact,  in  warm  climates  it  is  a  perennial  living  on 
from  year  to  year  just  as  our  shrubs  do. 

The  leaves  are  arranged  alternately  and  the  upper 


FARM  CROPS  63 

leaves  have  more  lobes  than  the  lower  ones.  One 
of  the  most  interesting  things  about  the  leaves  is 
that  they  secrete  nectar.  On  the  under  'side  of  the 
midrib  not  far  from  the  base  is  an  oval  shaped 
depression  or  pit.  In  this  the  sweet  nectar  collects. 
Sometimes  a  large  drop  stands  up  like  a  bit  of 
honey.  On  some  leaves  a  number  of  the  veins  have 
these  pits,  while  on  others  you  may  not  find  any. 

The  flower  has  at  the  lower  part  three  fringed 
bracts  that  enclose  the  bud  and  later  the  fruit.  When 
the  flower  first  opens  the  petals  are  a  creamy  white. 
A  little  later  they  become  a  pale  pink.  The  next 
day  they  have  changed  to  a  reddish  purple.  They 
then  begin  to  wither  slightly  and  usually  fall  by  the 
close  of  the  second  day.  The  plant  begins  to  blossom 
early  in  the  summer  and  continues  blossoming  all 
summer  and  early  fall,  so  you  may  find  on  the  plant 
at  the  same  time  flowers  and  fruit  in  all  stages  of 
development. 

The  ovary  develops  into  the  fruit  or  boll.  The 
fringed  bracts  still  remain  on  the  bolls.  Cotton  grow- 
ers call  these  the  "squares."  There  are  usually  five 
sections  in  the  boll,  which  split  open  at  the  top.  The 
fibers  are  fastened  to  the  blunt  upper  end  of  each 
seed.  They  are  long,  strong  fibers.  These  charac- 
teristics make  them  very  valuable  for  spinning  and 
weaving.  After  the  fibers  are  removed  the  seed 


64  STUDIES  IN  SCIENCE 

remains  covered  with  a  soft  coat  called  linters.  The 
outside  covering  of  the  seed  is  rather  hard.  The 
kernel  is  white  and  contains  considerable  oil. 

History.  Cotton  has  been  in  use  since  the  begin- 
ning of  written  history,  and  no  one  knows  how  long 
before.  Its  earliest  known  home  is  India,.  From  here 
it  was  introduced  into  Egypt  and  other  warm  coun- 
tries of  the  eastern  continent. 

Columbus  found  cotton  in  the  New  World  in  the 
West  Indies.  It  was  also  found  in  Mexico  and  South 
America  by  some  of  the  early  explorers. 

Cotton  was  introduced  into  the  southern  states 
early  in  the  history  of  the  colonies.  Two  distinct 
species  are  raised  here,  the  sea-island  and  the  upland 
cotton.  The  former  is  raised  along  the  coast  of  South 
Carolina,  Georgia,  Florida  and  in  the  West  Indies. 
The  upland  cotton  is  grown  in  most  of  the  other 
cotton  growing  states.  Cotton  may  be  raised  with 
profit  as  far  north  as  30°.  Look  on  a  map  to  find 
what  states  are  included  in  the  cotton  region. 

Uses,  The  fibers  are  removed  from  the  seeds  by 
a  machine  called  a  cotton  gin.  The  seeds  rest  against 
the  teeth  of  a  number  of  revolving  saws  which  pull 
the  fibers  from  the  seeds.  You  know  from  your  study 
of  history  how  very  important  the  invention  of  the 
cotton  gin  was.  After  the  cotton  is  ginned  it  is 
pressed  into  large  bales  and  shipped  to  the  cotton 


FARM  CROPS  65 

factories  where  the  fibers  are  spun  into  threads  and 
woven  into  cloth. 

The  seeds  are  taken  to  another  machine  which 
removes  the  linters.  This  product  is  used  in  the 
making  of  mattresses,  in  upholstering  furniture  and 
in  making  cotton  felt  cloth. 

The  hulls  are  removed  from  the  seeds,  crushed 
and  used  for  fertilizers  or  are  fed  to  cattle.  The 
kernels  are  pressed  in  a  great  pressing  machine  in 
order  to  obtain  the  oil  that  is  in  them.  The  oil  is  used 
for  cooking  purposes  and  to  serve  with  salads  instead 
of  olive  oil.  It  is  used  in  the  industries  especially 
in  mixing  paint  and  making  soap. 

The  pressed  remains  of  the  kernels  is  known  as 
oil-cake.  It  is  used  to  feed  cattle  and  is  usually  sold 
in  the  form  of  cotton-seed  meal. 

In  some  places  where  fuel  is  scarce  the  larger  parts 
of  the  cotton  stems  are  used  for  heating  purposes. 

Culture.  Cotton  is  planted  in  rows  from  three  to 
four  feet  apart.  It  is  cultivated  in  much  the  same 
way  that  corn  is.  Weeds  should  be  kept  down  and 
a  soil  mulch  produced  to  conserve  the  moisture.  Cot- 
ton growers  are  giving  much  attention  recently  to 
the  selection  of  good  seeds.  Plants  that  produce  bolls 
early  and  produce  them  in  large  numbers  are  marked 
and  the  seeds  from  these  plants  saved  for  the  next 
crop.  By  this  simple  selection  method  the  crop  in 


66  STUDIES  IN  SCIENCE 

some  regions  has  been  increased  from  15  to  25  per 
cent  in  a  period  of  three  years. 

Cotton  projects.  If  you  live  in  a  region  where 
cotton  is  raised,  you  should  plant  a  small  plot  of  your 
own.  Try  saving  the  seeds  from  the  plants  that  pro- 
duce well  and  see  to  what  extent  you  can  increase 
your  yield. 

Make  a  collection  of  all  the  different  products 
derived  from  cotton.  Mount  these  on  a  chart. 

Make  a  list  of  all  the  uses  of  cotton  that  you  know. 
How  valuable  is  the  cotton  crop  in  your  community? 
In  the  United  States? 


CHAPTER  III 

WEEDS 

Material.  A  collection  of  weed-plants,  leaves,  fruit, 
and  seeds.  Stiff  paper  for  charts  or  booklets. 

Study.  For  study  you  may  group  weeds  with 
reference  to  the  location  in  which  you  find  them 
growing;  as  garden,  lawn,  pasture  and  meadow,  road- 
side, vacant  lot  and  field. 

Go  into  your  garden,  yard  or  field  and  count  the 
number  of  different  kinds  of  weeds  that  are  grow- 
ing there.  Write  the  names  of  those  that  you  know. 
How  close  together  do  the  plants  stand!  To  what 
extent  are  different  species  growing  together? 

Make  a  special  study  of  each  kind.  Use  the  fol- 
lowing outline  to  keep  a  record  of  your  work: 

1.  Name: 

2.  Location:    garden,   lawn,   pasture,   roadside,  'cultivated  field, 
meadow,  etc. 

3.  Annual,  biennial,  perennial. 

4.  Habit  of  growth:   erect,  procumbent,  creeping,  climbing,  etc. 

5.  Characteristics  of  underground  parts:     a.  roots,  thick,  fleshy, 
long,  fibrous,     b.  underground  stem,  rootstock,  long  branching,  etc. 

6.  Leaves:  simple,  compound,  smooth,  hairy,  large,  small. 

7.  Flowers:  kind,  simple  or  composite;  dates  of  flowering,  spe- 
cial characteristics. 

67 


68  STUDIES  IN  SCIENCE 

8.  Fruit:   date  of  maturing;  seeds,  large,  small,  number,  special 
adaptations  for  distribution. 

9.  Methods  of  control. 

10.     Native  home  and  interesting  facts. 

Pigweed,  sometimes  called  careless  weed,  abundant 
in  many  gardens  and  fields,  is  a  good  one  with  which 
to  begin.  It  is  an  annual;  that  is,  it  starts  from  the 
seed  each  year,  produces  seed  and  then  dies.  It  has 
a  thick  taproot  with  many  branches.  The  leaves  are 
simple,  large  on  the  lower  branches  and  small  on  the 
upper  ones.  The  flowers  are  very  inconspicuous, 
growing  in  dense,  greenish  clusters. 

The  seeds  are  small  and  are  produced  in  great  num- 
bers. You  can  easily  estimate  the  number  of  seeds 
on  one  plant  by  counting  the  exact  number  on  a  small 
branch,  then  count  the  number  of  branches  of  the 
same  size  and  calculate  the  entire  number  of  seeds. 
The  easiest  way  to  get  the  seeds  is  to  rub  them  out 
of  the  chaff  onto  a  sheet  of  paper.  If  you  have 
patience  you  can  remove  all  the  seeds  from  a  large 
plant  and  put  them  into  a  jar  or  bottle.  This  gives 
a  very  accurate  idea  of  the  great  number  of  seeds 
that  one  plant  produces,  and  explains  why  the  weed 
is  so  abundant. 

Compare  with  pigweed  other  annuals  as  smart- 
weed,  foxtail  grass,  and  rag  weed,  noting  character- 
istics that  are  common,  and  those  that  are  dissimilar. 
Find  some  plants  whose  stems  were  cut  off  a  few 


WEEDS  69 

inches  above  the  ground  earlier  in  the  season,  and 
describe  what  has  taken  place. 

Find  in  vacant  lots,  pastures  or  roadsides,  some 
types  of  biennial  weeds;  that  is,  weeds  that  grow 
from  seed  the  first  year,  blossom  the  second  year,  bear 
fruit  and  die. 

Some  of  the  most  familiar  biennials  are  burdock, 
field  or  bull  thistles,  wild  parsnip  and  wild  carrot. 
Find  plants  of  the  first  year's  growth  and  those  of 
the  second.  Compare  them  noting  differences. 

In  lawns,  pastures  and  in  some  cultivated  fields 
you  will  find  weeds  whose  underground  parts  con- 
tinue to  live  year  after  year.  .Each  year  they  send 
up  new  stems  and  leaves,  blossom  and  bear  seeds. 
These  are  perennials.  Dandelion,  plantain,  curly 
dock,  creeping  mallow  or  cheese  weed  are  common 
perennials.  Make  careful  observation  of  their  under- 
ground parts  to  determine  how  they  live  through  the 
winter.  Note  also  any  special  adaptations  they  may 
have  to  spread  by  means  of  roots  or  underground 
stems.  Summarize  the  great  number  of  character- 
istics that  such  a  perennial  as  the  dandelion  has  that 
make  it  a  successful  lawn  plant. 

Compare  weeds  of  the  same  species  growing  in 
different  locations,  as  a  dandelion  on  the  lawn  with 
one  growing  in  tall  grass.  How  do  you  account  for 
the  difference! 


70  STUDIES  IN  SCIENCE 

Begin  at  once  making  a  collection  of  the  weeds 
of  your  neighborhood.  Press  a  leaf  of  each  species 
and  when  possible  a  flower.  Preserve  also  fruiting 
heads  or  pods  and  seeds.  Mount  your  specimens  on 
cardboard  making  a  weed  chart  or  booklet. 

The  easiest  way  to  press  the  plants  is  to  spread 
them  out  on  a  piece  of  newspaper,  taking  care  to 
smooth  out  the  leaves,  then  place  several  layers  of 
the  paper  on  top.  Lay  them  down  flat  and  put  a 
weight  upon  them.  After  an  interval  of  several  days 
all  moisture  will  have  been  absorbed  and  the  plants 
will  be  ready  for  mounting.  There  are  two  ways  to 
mount  them.  You  may  use  small  strips  of  paper, 
with  mucilage  on  one  side,  to  form  loops  over  the 
stems ;  or  you  may  sew  the  specimen  fast  to  the  sheet. 

Discussion.  Most  garden  weeds  and  those  found 
in  cultivated  fields  are  annuals.  You  found  that 
pigweed,  foxtail,  smartweed  and  crab-grass  each  pro- 
duces a  large  number  of  seeds.  This  is  character- 
istic of  most  annuals  and  is  of  great  importance  since 
these  plants  are  wholly  dependent  upon  seeds  for 
reproduction. 

An  interesting  fact  about  the  seeds  is  that  they 
do  not  all  germinate  and  grow  at  the  same  time.  No 
doubt  you  have  weeded  your  garden  during  the 
growing  season  and  then  have  gone  back  within  a 
week  to  find  another  crop  of  weeds  of  the  same  kind. 


WEEDS  71 

If  you  continue  this  all  summer,  the  weeds  will  still 
continue  to  grow  to  a  certain  extent.  The  seeds  of 
some  weeds  probably  remain  a  number  of  years  in 
the  soil  before  they  finally  germinate  and  grow. 
Agriculturists  have  found  by  experiment  that  only 
one  of  the  two  seeds  of  the  cocklebur  grows  the  first 
season.  The  other  one  may  grow  the  second  year 
or  may  wait  several  years. 

Another  characteristic  that  is  an  advantage  to 
annuals  is  that  they  may  start  to  grow  in  the  middle 
of  the  summer  after  cultivation  has  ceased  and  yet 
succeed  in  maturing  their  seeds  before  cold  weather. 
Some  of  them,  like  the  pigweed,  cocklebur,  foxtail 
and  others,  when  cut  off,  send  out  new  branches  from 
the  injured  stems,  blossom  and  bear  seeds  in  spite 
of  the  injury. 

The  dandelion  has  many  characteristics  that  make 
it  a  successful  plant.  It  is  so  hardy  that  it  can  blos- 
som and  produce  seeds  when  the  temperature  is 
quite  low.  In  some  places  where  it  is  sheltered  even 
in  the  North  Central  States  it  produces  seeds  all 
winter.  Its  large  root  provides  food  for  rapid  growth 
in  the  spring.  You  probably  found  in  the  heart  of 
the  rosette  tiny  buds  that  are  ready  to  open,  up  just 
as  soon  as  conditions  are  favorable.  The  growing 
center  of  the  rosette  is  below  the  surface  of  the  soil 
so  that  a  lawn  mower  does  not  injure  it  in  the  least. 


72  STUDIES  IN  SCIENCE 

In  fact,  the  mower  is  a  friend  of  the  dandelion,  since 
it  cuts  away  the  grass  allowing  plenty  of  light  to 
reach  the  weed.  The  milky  secretion,  which  is  bitter, 
is  not  liked  by  most  animals,  so  the  plant  is  not  cropped 
when  it  grows  in  pastures.  In  addition  to  all  these 
characteristics  for  successful  growth,  it  has  a  great 
number  of  seeds  that  may  be  carried  long  distances 
by  the  wind. 

The  dandelion  leaves  are  used  for  greens  and  salads 
and  the  root  for  medicine,  so,  while  we  often  regard 
it  as  an  undesirable  weed  in  the  lawn,  it  also  has  use- 
ful qualities.  In  some  places  near  large  cities  it  is 
grown  in  gardens  to  supply  the  market  with  greens. 

The  thistle,  burdock,  and  other  biennials  grow 
from  seeds  and  produce  large  fleshy  roots  and  a  num- 
ber of  leaves  the  first  year.  The  second  year  they 
send  up  a  flowering  stem  and  use  the  great  supply  of 
food  they  have  stored  in  the  roots  to  produce  seeds. 

Annuals  are  usually  found  in  gardens  and  culti- 
vated fields.  Since  they  start  from  seeds  each  year 
the  open  plowed  ground  gives  them  a  chance  to  get 
a  foothold.  They  have  little  opportunity  to  start  in 
lawns,  meadows  and  pastures  because  the  space  is 
already  .occupied,  and  there  is  no  good  place  for  the 
seeds  to  settle  down  and  germinate. 

Perennials  are  most  abundant  in  pastures,  old  mead- 
ows and  roadsides;  but  even  perennials  have  a  hard 


WEEDS  73 

time  to  gain  a  foothold  in  grassy  areas.  Some  of  them 
get  fairly  well  started  but  are  crowded  out  by  the 
grasses.  The  only  perennials  that  succeed  in  hold- 
ing their  places  are  those  that  have  special  adapta- 
tions like  the  dandelion,  the  Canada  thistle,  milk- 
weed, curlydock  and  different  kinds  of  daisies.  Per- 
ennials when  once  established  are  the  hardest  of 
all  weeds  to  combat,  because  they  not  only  produce 
seeds  for  new  plants  but  the  old  plants  continue 
to  live.  Many  of  them  also  spread  by  their  under- 
ground stems. 

There  are  a  few  perennials  that  thrive  well  in 
cultivated  soils.  Among  them  are  the  wild  morn- 
ing-glories, one  with  a  large  white  flower,  the  other 
with  a  pink  flower  sometimes  called  wild  sweet 
potato.  Quack  grass  is  perhaps  even  worse  than 
the  wild  morning-glories.  All  of  these  spread  by 
underground  stems  called  rootstocks.  A  small  piece 
of  stem  under  right  conditions  starts  a  new  plant, 
so  that  cultivation  often  tends  to  scatter  these  weeds 
instead  of  destroying  them. 

Many  weeds  of  all  three  classes  possess  special 
devices  for  distributing  their  seeds  that  aid  them 
in  getting  possession  of  new  fields.  You  have 
observed  the  feathery  pappus  fliers  of  the  thistles, 
wild  lettuce,  and  dandelion,  the  burs  of  cocklebur 
and  burdock,  the  tumble  weeds  that  roll  along  scat- 


74  STUDIES  IN  SCIENCE 

tering  their  seeds  as  they  go,  as  Eussian  thistle,  and 
old  witch  grass.  Some  smooth  seeds  of  such  plants 
as  the  ragweed,  velvetweed,  and  pigweed  are  car- 
ried long  distances,  and  are  blown  over  the  snow 
and  ice  in  the  winter  time.  Water  helps  to  dis- 
tribute seeds  by  washing  them  down  slopes,  by  carry- 
ing them  in  streams  and  scattering  them  over  the 
land  during  the  high  waters  in  the  spring. 

Why  weeds  are  not  desirable.  Make  a  list  of  all 
the  reasons  you  can  think  of  why  you  do  not  wish 
weeds  to  grow  in  your  fields  and  garden. 

1.  They  use  up  moisture  and  mineral  foods  that 
you  would  like  to  have  left  for  your  cultivated  crops. 

2.  As   a   rule,   they   are   rapid   growers   and   can 
easily  shade  the  smaller  cultivated  plants. 

3.  Many   of  them  can  thrive  in   crowded   condi- 
tions better  than  some  of  our  cultivated  crops. 

4.  In  grain  fields  they  increase  the  cost  of  har- 
vesting by  occupying  a  large  space  in  the  sheaves. 

5.  In  threshing,  some  of  the  seeds  are  certain  to 
become  mixed  with  the  grain,  thus  making  it  inferior 
either  for  market   or  seeding  purposes.     The   same 
thing  may  be  said  of  weeds  in  meadows.     Hay  with 
a  large  per  cent  of  weeds  is  not  as  valuable  as  pure 
hay. 

6.  Some  weeds  are  detrimental  because  they  are 
poisonous  to  stock. 


WEEDS  75 

7.  Some   provide   a   shelter   for  injurious   insects 
during  the  winter. 

8.  Many  weeds  are  such  coarse,  unsightly  plants 
that  we  do  not  like  to  see  them  around  a  home  or 
farm. 

Getting  rid  of  weeds.  How  to  get  rid  of  weeds 
is  a  problem  that  all  gardeners  and  farmers  must  face. 
The  more  you  know  about  the  lives  and  habits  of 
these  plants,  the  better  able  you  will  be  to  exter- 
minate them.  Annuals  have  but  one  way  to  repro- 
duce themselves;  if  you  can  prevent  their  producing 
seeds,  it  will  not  take  many  years  to  eradicate  them 
altogether.  Rotation  of  crops  aids  greatly  in  con- 
trolling these  weeds. 

Biennials  may  be  controlled  in  much  the  same 
way  as  annuals.  If  they  are  dug  out  the  first  year 
or  cut  down  and  burned  the  second  year  before  the 
seeds  mature,  they  are  easily  destroyed.  It  does 
little  good  to  cut  off  their  tops  before  they  send 
up  their  flowering  stems,  for  they  will  continue  to 
grow  and  send  up  new  stems  until  they  have  a 
chance  to  produce  flowers  and  seeds. 

Perennials  are  harder  to  handle  since  they  are 
not  dependent  upon  seeds  for  reproduction,  but  con- 
tinue to  live  and  spread  year  after  year.  Sometimes 
a  change  of  crop  will  help  to  eradicate  them.  Pas- 
tures and  meadows  that  are  badly  infested  with 


76  STUDIES  IN  SCIENCE 

perennials  and  biennials  should  be  plowed  up  and 
planted  to  grains.  Perennials  in  small  plots  may 
be  dug  up  root  and  all  and  burned.  A  method 
sometimes  used  is  to  cover  a  small  plot  with  a 
thick  coating  of  straw  or  manure.  Sometimes  tar 
paper  is  used  instead.  This  covering  prevents  the 
leaves  from  manufacturing  food  since  they  are 
entirely  shut  off  from  the  sunlight.  The  roots  can- 
not live  long  without  food  so  the  plants  are  really 
starved  to  death.  This  method  is  too  expensive 
to  use  except  in  small  tracts.  Another  method  that 
is  successful  although  very  expensive  is  known  as 
fallowing.  Instead  of  trying  to  raise  a  crop  of  any 
kind  the  farmer  plows  under  the  first  crop  of  weeds 
in  the  spring,  then  discs  the  soil  every  few  days 
during  the  growing  season  so  that  no  leaves  have 
an  opportunity  to  get  above  the  ground  and  manu- 
facture food. 

You  will  be  interested  to  know  that  most  of  our 
worst  weeds  are  not  natives  of  America.  They  have 
been  introduced  from  other  countries,  usually  with 
the  seeds  of  cultivated  crops.  Some  were  brought 
over  by  the  early  colonists.  Others  have  come  in 
rather  recently.  Most  of  them  possess  character- 
istics that  enable  them  not  only  to  gain  a  foothold 
in  our  soil  but  to  keep  possession  even  in  the  face 
of  hard  conditions. 


WEEDS  77 

LIST  OF  COMMON  WEEDS 
EXPLANATION  OF  TEEMS  AND  SYMBOLS 

The  letters  (A),  (B),  (P),  following  the  name  indicate  whether 
the  weed  is  an  annual,  a  biennial,  or  perennial. 

The  scientific  name  is  found  in  parentheses  after  the  common 
name  of  each  weed. 

Fam.  stands  for  the  name  of  the  botanical  family  to  which  the 
plant  belongs. 

Hab.  stands  for  habitat  and  tells  the  place  in  which  the  weed  is 
found  growing  most  abundantly. 

N.  H.  gives  the  native  home  of  the  weed  or  the  country  from  which 
it  has  been  introduced. 

Char.  Under  this  term  the  characteristics  that  make  the  weed 
hard  to  combat  are  given. 

Control.  Some  of  the  best  methods  of  combatting  each  weed  are 
suggested. 

Butter  'print,  velvet  leaf:  (A) ;  (Abutilon,  abutilon) ;  Family, 
Mallow;  Hab.,  Cultivated  fields,  gardens;  N.  H.,  Asia;  Char.,  Many 
seeds  scattered  by  the  wind  shaking  the  tall  stem.  Leaves  covered 
with  soft  hairs  which  enable  the  plant  to  stand  drought.  Control, 
Pulling  or  hoeing  before  plants  blossom.  Cutting  mature  plants, 
piling  and  burning. 

Burdock:  (B) ;  (Actium,  minus);  Fam.,  Thistle;  Hab.,  Vacant 
lots,  waste  places,  fence  corners;  N.  H.,  Europe;  Char.,  Deep  thick 
roots,  lower  leaves  very  large.  Fruit  a  bur.  Seeds  scattered  by 
animals;  Control,  Deep  cutting  below  crown  before  flowers  appear. 
Cutting,  piling,  and  burning  mature  plants. 

BuckJiorn:  (P) ;  (Plantago  lanceolata) ;  Fam.,  Plantain;  Hab., 
Fields,  meadows,  pastures;  N.  H.,  Europe  and  Asia;  Char.,  Thick 
rootstock  which  lives  over  winter.  Flowers  and  bears  seeds  from 
April  to  October.  Seeds  scattered  in  clover,  alfalfa,  and  other  hays; 
Control,  Plowing  under  meadows  or  pastures  and  cultivating  thor- 
oughly. Where  plants  are  few,  cutting  out. 

Wild  carrot,  Queen  Anne's  lace:  (B) ;  (Daucus  carota) ;  Fam.. 
Parsley;  Hab.,  Roadsides,  lawns  and  meadows;  N.  H.,  Europe  and 
Asia;  Char.,  Long  root,  numerous  seeds  distributed  by  wind,  birds 
and  water;  Control,  Cutting  roots  well  below  crown.  Repeated  cut- 
ting during  summer. 


78  STUDIES  IN  SCIENCE 

Canada  thistle:  (P) ;  (Carduus  Arvensis) ;  Fam.,  Thistle;  Hab., 
Pastures,  waste  places;  N.  H.,  Europe;  Char.,  Spreads  by  a  run- 
ning rootstock  from  2  to  3  ft.  deep.  Seeds  scattered  by  wind.  .Con- 
trol, Covering  with  tar  paper  or  other  material  for  an  entire  season  or 
two  to  starve  out  the  rootstocks.  Repeated  cutting  during  the  grow- 
ing season  for  at  least  two  years. 

Chickiueed:  (A);  (Alsine  media);  Fam.,  Pink;  Hab.,  Moist 
places,  edges  of  gardens,  meadows,  lawns;  N.  H.,  Europe  and  Asia; 
Char.,  Blossoms  all  spring  and  summer.  Many  seeds;  Control, 
Rotation  of  crops.  Crowding  out  by  winter  crops  as  rye,  or  crimson 
clover. 

Cocklebur:  (A);  (Xanthium  glabratum) ;  Fam.,  Ragweed;  Hab., 
Cultivated  fields,  especially  in  moist  ground,  in  cornfields;  N.  H., 
Europe;  Char.,  Hardy,  rapid  grower.  Sends  out  new  branches  when 
stem  is  cut  off.  Bur  widely  scattered  by  animals;  Control,  Pulling 
before  burs  are  formed.  Burning  mature  plants. 

Corn-cockle:  (A);  (Agrostemma  Githago) ;  Fam.,  Pink;  Hab., 
Grain  fields,  especially  wheat  and  rye;  N.  H.,  Europe  and  Asia; 
Char.,  Many  small  seeds.  Blossoms  all  summer;  Control,  Hand 
pulling,  screen  grain,  seeds,  crop  rotation. 

Crab-grass,  finger-grass:  (A);  (Syntherisima  Sanguinalis) ; 
Fam.,  Grass;  Hab.,  Gardens  and  cultivated  fields;  N.  H.,  Europe; 
Char.,  Many  small  seeds.  Takes  root  at  joints;  Control,  Hand  pull 
ing,  burn  plants,  burn  stubblefields. 

Creeping  Mallow,  Cheeseiveed:  (P) ;  (Malva  rotundifolia) ; 
Fam.,  Mallow;  Hab.,  Dooryards,  waste  places,  gardens;  N.  H.,  Eu- 
rope and  Western  Asia;  Char.,  Very  long  root.  Stands  drought; 
Control,  Thorough  cultivation,  digging  out  by  root. 

Curled  dock,  yellow:  (P) ;  (Rumex  Crispus) ;  Fam.,  Buckwheat; 
Hab.,  Waste  places,  old  pastures;  N.  H.,  Europe  and  Asia;  Char., 
Long,  thick  root.  Many  seeds.  Control,  Cutting  root  several  inches 
below  surface  before  seeds  ripen. 

Dandelion:  (P) ;  (Taraxacum  taraxacum);  Fam.,  Chicory; 
Hab.,  Lawns,  pastures,  roadsides;  N.  H.,  Europe,  Asia,  and  probably 
North  America;  Char.,  Long,  thick  root.  Many  seeds,  widely  dis- 
tributed by  wind.  Blossoms  all  year.  Control,  cutting  root  far 
below  surface  before  plant  goes  to  seed. 

Field  bindweed,  small  bindweed:  (P) ;  (Convolulus  arvensis) ; 
Fam.,  Morning  Glory;  Hab.,  Cultivated  fields;  N.  H.,  Europe  and 
Asia;  Char.,  Spreading  by  rootstocks  which  form  buds  and  start 


WEEDS  79 

ne\v    plants;    Control,    Cutting    tip    frequently    during    the    entire 
summer.     Smothering  with  paper  or  straw. 

Field  sorrel,  horse  sorrel:  (P) ;  (Rumex  acetosa) ;  Fam.,  Buck 
wheat;  Hab.,  Pastures,  meadows,  cultivated  fields;  N.  H.,  Europe; 
Char.,  Spreading  by  running  rootstocks.  Numerous  seeds.  Con- 
trol, Crowding  out  with  clover  and  grasses.  Lime  on  soil  to  enable 
clover  to  grow  well. 

Foxtail,  yellow:  (A);  Pigeon  grass;  (Ixophorus  glaucus) ; 
Fam.,  Grass;  Hab.,  Garden,  cultivated  fields;  N.  H.,  Europe;  Char., 
Many  seeds  retaining  vitality  for  years.  Send  out  new  stems  when 
cut  off.  Strong  fibrous  roots.  Control,  Mowing  and  burning  stub- 
blefields.  In  garden  pulling  out  by  roots  when  soil  is  soft  after  a 
rain. 

Foxtail,  green:  (A);  (Ixophorus  viridis) ;  Fam.,  Grass;  Hab., 
Gardens,  cultivated  fields;  N.  H.,  Europe;  Char.,  Same  as  above. 
Control,  Same  as  yellow  foxtail. 

Horse  nettle:  (P) ;  (Solanum  Carolinense) ;  Fam.,  Potato; 
Hab.,  Cultivated  fields,  pastures;  N.  H.,  United  States  and  Canada; 
Char.,  Numerous  seeds.  Spreads  also  by  a  strong  rootstock.  Ex- 
ceedingly hardy;  Control,  Cutting  off  close  to  ground  and  salting. 

Horsctveed,  colt's  tail:  (A);  (Laptilon  Canadense) ;  Fam.,  This- 
tle; Hab.,  Pastures,  roadsides,  waste  places,  gardens;  N.  H.,  North 
America  and  South  America;  Char.,  Many  seeds  with  pappus  dis- 
tributed by  wind;  Control,  Cutting  and  burning.  Pulling  before 
seeds  ripen. 

Jimson-iveed:  (A);  (Datura  Stromonium) ;  Fam.,  Potato;  Hab., 
Waste  places,  barnyards;  N.  H.,  Tropical  Asia;  Char.,  Many  seeds, 
Hardy;  Control,  Pulling  when  young.  Cultivation. 

Knotgrass,  doorwecd:  (A);  (Polygonum  aviculare) ;  Fain., 
Buckwheat;  Hab.,  Yards,  roadsides,  along  walks;  N.  H.,  North 
America,  Europe,  and  Asia;  %Char.,  Spreading  close  to  ground,  not 
easily  injured  by  trampling;  Control,  Pulling  or  cutting  before  seeds 
ripen. 

Lamb's  quarters,  goosefoot:  (A);  (Chenopodium  Album); 
Fam.,  Goosefoot;  Hab.,  Gardens,  cultivated  fields;  N.  H.,  Europe 
and  Asia;  Char.,  Many  seeds,  produces  new  stems  when  cut  off; 
Control,  Pulling  or  hoeing  before  seeds  ripen.  Thorough  cultivation. 

Lamb's  quarters,  city  goosefoot:  (A);  (Chenepodium  urbicum) ; 
Fam.,  Goosefoot;  Hab.,  Gardens,  along  walks,  waste  places;  N.  H., 
Europe;  Char.,  Same  as  last  and  control  the  same. 


80  STUDIES  IN  SCIENCE 

Lettuce,  wild,  prickly  lettuce:  (A);  (Lactuca  Scariola) ;  Fain., 
Chicory;  Hab.,  Waste  places,  gardens,  old  fields;  N.  H.,  Europe; 
Char.,  Many  seeds  with  pappus,  scattered  by  the  wind.  Prickles 
protect  it  from  animals.  Plants  that  start  late  in  summer  live  over 
winter;  Control,  Early  cultivation  or  hoeing  in  spring  to  kill  winter 
plants.  Cutting  and  burning  before  seeding. 

Morning-glory,  wild,  hedge  bindweed:  (P) ;  (Convolvulus  sep- 
ium);  Fam.,  Morning-glory;  Hab.,  Cultivated  fields,  fence  rows; 
N.  H.,  North  America,  Europe  and  Asia;  Char.,  Spreads  by  seeds 
and  running  rootstocks;  Control,  Cultivating  every  ten  days  or  two 
weeks  all  summer,  in  small  plots,  smothering  by  tar  paper. 

Milkweed:  (P) ;  (Asclepias  syriaca) ;  Fam.,  Milkweed;  Hab., 
Cultivated  fields,  meadows,  pastures;  N.  H.,  All  parts  of  United 
States;  Char.,  Seeds  with  pappus  widely  scattered  by  wind.  Spreads 
also  by  deep  running  rootstock;  Control;  Repeated  cutting  during 
the  entire  summer,  continued  for  two  years. 

Mullein:  (B) ;  (Verbascum  thapsus) ;  Fam.,  Figwort;  Hab., 
Pastures,  roadsides;  N.  H.,  Europe;  Char.,  Many  small  seeds  which 
retain  vitality  for  years.  Rosette  of  thick  leaves  close  to  ground, 
well  protected;  Control,  Cutting  off  rosette  below  crown  in  fall  or 
early  spring. 

Mustard,  wild,  cJiarlock:  (A);  (Brassica  arvensis) ;  Fam.,  Mus- 
tard; Hab.,  Grain  fields,  especially  oats,  meadows;  N.  H.,  Europe; 
Char.,  Many  seeds  which  mix  with  grain  when  threshed;  Control, 
Burning  stubble  or  harrowing  to  start  seeds.  Plowing  under  in 
fall.  Pasture  with  sheep. 

Old  witch  grass,  tickle  grass:  (A);  (Panicum  capillare) ;  Fam., 
Grass;  Hab.,  Gardens,  cultivated  fields,  stubblefield;  N.  H.,  South- 
ern Canada  and  all  of  United  States;  Char.,  Many  seeds,  rapid 
grower.  Plant  breaks  off  in  the  fall  near  the  ground;  Control, 
mowing  and  burning. 

Parsnip,  wild:  (B) ;  (Pastinaca  s'ativa) ;  Fam.,  Parsley;  Hab., 
Waste  places,  roadsides;  Char.,  Strong  root,  hardy  plant,  many 
seeds;  Control,  Cutting  out  below  crown  first-year  plants.  Mowing 
and  burning  second  year. 

Plantain:  (P) ;  (Plantago  major);  Fam.,  Plantain;  Hab.,  Lawns, 
roadsides,  pastures;  N.  H.,  Europe;  Char.,  Many  seeds,  rosette  of 
leaves  close  to  ground,  stands  trampling;  Control,  In  yard,  cutting 
below  surface.  In  pastures,  crowding  out  writh  clover. 

Pepper  grass,  tongue-grass:     (A);   (Lepidium  Virginicum) ;  Fam., 


WEEDS  81 

Mustard;  Ilab.,  Dooryards,  waste  places,  gardens,  meadows;  N.  H., 
Canada  and  United  States;  Char.,  Many  seeds,  plants  start  in  the 
fall  and  live  over  winter;  Control,  Pull  up  by  roots  in  lawns.  Thor- 
ough cultivation  in  fields. 

Pigiveed,  careless  weed:  (A) ;  (Amaranthus  retroflexus) ;  Fam., 
Goosefoot;  Hab.,  Gardens,  cultivated  fields;  N.  H.,  Tropical  America; 
Char.,  Numerous  small  seeds.  Send  out  new  stems  that  produce  seed 
when  cut  off  near  the  ground.  Very  hardy;  Control,  Pulling  before 
seeds  ripen.  Burning  in  fall  all  the  plants  that  have  gone  to  seed. 

Pigweed,  red-stemmed:  (A) ;  (Amaranthus  hybridus) ;  Fam., 
Goosefoot;  Hab.,  Garden,  fields;  N.  H.,  Tropical  America;  Char., 
Same  as  above.  Control,  Same. 

Purslane,  pussley:  (A) ;  (Portulaca  oleraceus) ;  Fam.,  Pur- 
slane; Hab.,  Gardens,  cultivated  fields;  N.  H.,  Southern  United 
States,  and  Tropical  America;  Char.,  Blossoms  and  bears  seed  all 
summer.  Seeds  many,  plant  very  juicy.  Can  stand  drought;  Con- 
trol, Pulling  out  when  young,  drying  and  burning,  or  feeding  to  hogs. 

Pungent  meadow-grass:  (A);  (Eragrostis  major) ;  Fam.,  Grass; 
Hab.,  Gardens,  waste  places;  N.  H.,  Europe;  Char.,  Many  seeds, 
strong  roots;  Control,  Hoe  or  plow  out  before  seeding. 

Quack-grass,  couch-grass:  (P) ;  (Agropyron  repens) ;  Fam., 
Grass;  Hab.,  Grain  fields,  lawns,  gardens;  N.  H.,  Europe;  Char., 
Strong  rootstock  that  spreads  rapidly.  Clings  so  firmly  in  soil  that 
it  cannot  be  pulled  up;  Control,  Plow  in  fall,  harrow  or  rake,  pile 
and  burn  plants.  Two  plowings  may  be  necessary. 

Ragweed,  common:  (Ambrosia  artemisiaefolia) ;  Fam.,  Rag- 
weed; Hab.,  Stubblefield,  cornfield,  pastures,  gardens;  N.  H.,  North 
America,  South  America;  Char.,  Many  seeds.  Can  grow  and  ma- 
ture seeds  late  in  summer.  Can  stand  dry  weather;  Control,  Work- 
ing and  burning  stubble.  Early  fall  plowing. 

Ragweed,  horseivood:  (A);  (Ambrosia  trifida) ;  Fam.,  Ragweed; 
Hab.,  Roadsides,  along  streams,  fence  corners;  N.  H.,  United  States 
and  Canada;  Char.,  Many  seeds  carried  by  birds,  not  a  very  bad 
weed;  Control,  Pulling  before  seeding.  Burning  stubble.  Pasturing 
with  sheep. 

Shepherd's  purse:  (A);  (Bursa  bursa  pastor  is );  Fam.,  Mus- 
tard; Hab.,  Waste  places,  gardens,  lawns;  N.  H.,  Europe;  Char., 
Plants  that  start  late  in  the  summer  live  over  winter  and  produce 
seeds  early.  Flowers  all  summer;  Control,  Hand  pulling  from  lawns. 
Fall  plowing  in  gardens  and  fields. 


82  STUDIES  IN  SCIENCE 

Sow-thistle:  (A);  (Sonchus  oleraceus) ;  Fam.,  Chicory;  Hab., 
Waste  places,  roadsides,  fence  corners;  N.  H.,  Europe,  Asia;  Char., 
Many  seeds  with  pappus,  distributed  by  the  wind;  Control,  Cutting 
while  young,  burning  mature  plants. 

Spanish  needle,  "bur  marigold:  (A) ;  (Bidens  connata) ;  Fam., 
Thistle;  Hab.,  Low  regions  in  fields  and  pastures;  N.  H.,  United 
States  and  Canada;  Char.,  Seeds  with  bristles  that  stick  to  animals 
and  clothing;  Control,  Thorough  cultivation,  cutting  before  seeds 
ripen. 

Smartwecd,  spotted  smartweed:  (A) ;  (Polygonium  persicaria) ; 
Fam.,  Buckwheat;  Hab.,  Gardens,  cultivated  fields,  especially  low 
regions;  N.  H.,  Europe;  Char.,  Seeds  many,  distributed  in  grain; 
Control,  Cutting  before  seeds  ripen,  burning  stubble,  pulling  or 
hoeing  in  gardens. 

Spurge,  spotted:  (A);  (Euphorbia  maculata) ;  Fam.,  Spurge; 
Hab.,  Gardens,  cultivated  fields,  roadsides;  N.  H.,  North  America.; 
Char.,  Many  seeds.  Grows  prostrate  forming  a  mat  on  the  ground. 
Control,  Hoeing  or  pulling,  through  cultivation. 

Spurge,  upright,  spotted  spurge:  (A);  (Euphorbia  nutens) ; 
Fam.,  Spurge;  Hab.,  Gardens,  cultivated  fields,  roadsides;  N.  H., 
North  America;  Char.,  Many  seeds.  Same  as  above  but  stands  erect 
instead  of  spreading  on  ground;  Control,  Hoeing  or  pulling; 
thorough  cultivation. 

Spreading  orache:  (A) ;  (Atriplex  patula) ;  Fam.,  Goosefoot; 
Hab.,  Roadsides,  along  walks,  waste  places;  N.  H.,  Europe  and  Asia; 
Char.,  Many  seeds,  rapid  grower,  many  branches;  Control,  Pulling 
or  hoeing  before  flowers  appear. 

Squirrel-grass,  wild  Parley:  (P) ;  (Hordeum  jubatum) ;  Fam., 
Grass;  Hab.,  Roadsides,  fence  corners,  meadows;  N.  H.,  Canada  and 
Northern  United  States;  Char.,  Long  beards,  seeds  scattered  by 
wind  and  water;  Control,  Pulling,  cutting  or  hoeing  before  seeds 
ripen. 

Tunibleweed:  (A);  (Amaranthus  graecizans) ;  Fam.,  Amaranth; 
Hab.,  Grain  fields,  old  fields,  roadsides;  N.  H.,  Tropical  America; 
Char.,  Many  branches  forming  a  round  head  which  breaks  off  close 
to  the  ground,  rolls  over  and  over  scattering  the  many  small  seeds; 
Control,  Burning  the  mature  weeds  in  the  fall.  Pulling  or  hoeing 
before  seeding. 

Thistle,  pasture  or  lull  thistle:  (B) ;  (Carduus  lanceolatus) ; 
Fam.,  Thistle;  Hab.,  Pastures,  roadsides;  N.  H.,  Europe  and  Asia; 


WEEDS  .  83 

Char.,  Deep  root,  many  sharp  spines,  seeds  scattered  by  wind;  Con- 
trol, Cutting  off  root  well  below  the  crown. 

Vervain  Hue,  wild  hysop:  (P) ;  (Verbena  Castata) ;  Fain.,  Ver- 
vain; Hab.,  Pastures,  meadows,  waste  places;  N.  H.,  Southern  Can- 
ada and  United  States;  Char.,  Hardy,  stands  drought,  not  a  very 
bad  weed;  Control,  Cultivation  and  mowing. 

White  top,  daisy  fleabane:  (A) ;  (Erigeron  annuus) ;  Fain., 
Thistle;  Hab.,  Meadows,  pastures,  oat  fields;  N.  H.,  Europe;  Hab., 
Plants  started  in  the  fall  live  over  winter  and  blossom  early.  Many 
seeds;  Control,  If  very  abundant  in  meadows  plow  under  and  plant 
corn.  Pull  out  by  roots. 

Wild  bucTtiolieat,  fcZacfc  "bindweed:  (A);  (Polygonum  convolvu- 
lus) ;  Fam.,  Buckwheat;  Hab.,  Cornfield,  grain,  fence  rows,  gardens; 
N.  H.,  Asia.  Brought  here  from  Europe;  Char.,  Climb  or  twine 
around  corn  and  wheat.  Many  seeds;  Control,  Early  fall  plowing 
and  harrowing.  Pulling  or  mowing  and  burning  before  seeds  ripen. 

Wild  sweet  potato:  (P)  (Ipomea  pandurata) ;  Fam.,  Morning- 
glory;  Hab.,  Cultivated  fields,  meadows;  N.  H.,  Canada  and  United 
States;  Char.,  Thick,  fleshy  roots  that  send  up  new  plants.  Many 
seeds;  Control,  Deep  cutting,  salting,  mowing  and  burning  tops 
several  times  during  the  season. 

Yarrotv,  milfoil:  (P) ;  (Achillea  millefolium) ;  Fam.,  Thistle; 
Hab.,  Pastures,  roadsides,  lawns;  N.  H.,  United  States,  Europe,  and 
Asia;  Char.,  Spreads  by  horizontal  rootstocks,  very  hardy;  Con- 
trol, Pulling,  cutting  and  burning. 


CHAPTER  IV 

TEEE  STUDIES 

Material.  Trees  of  the  neighborhood,  leaves,  twigs, 
fruit  and  seeds  for  indoor  study  and  for  charts  and 
booklets.  , 


"-Spray 


Large 


Irinik  or  bole 


Fig.  16.    The  parts  of  a  tree. 

Study.     How  many  trees  in  your  neighborhood  do 
you  know?     If  you  do  not  know  most  of  them  set 

84 


TREE  STUDIES  35 

about  learning  them.  Do  not  be  satisfied  simply 
to  distinguish  an  oak  from  a  maple  or  a  pine  from 
a  fir,  but  learn  the  exact  species  of  every  tree  in 
your  community. 

Select  a  special  tree  for  study.  Stand  a  short  dis- 
tance from  it  and  name  all  the  parts  you  can  see. 
If  you  do  not  know  the  names,  consult  Fig.  16. 

What  is  the  shape  of  the  crown?  Is  the  top 
rounded,  flat  or  pointed?  Is  it  dense  or  open?  What 


Fig.  17.     Tree  forms:     spherical  and  broadly  conical. 

is  the  character  of  the  branching?  Does  the  trunk 
break  up  into  a  number  of  branches  or  extend  un- 
broken to  the  top?  Note  the  twigs  and  determine 
whether  they  are  thick  and  erect,  slender  and  droop- 
ing, few  or  many.  Examine  the  bole;  what  is  its 
color?  Compare  with  the  branches  and  twigs. 
Describe  the  bark.  Is  it  smooth,  furrowed  or  scaly? 
Are  the  furrows  or  fissures  deep  or  shallow?  Do 
they  extend  up  and  down  or  around  the  trunk? 


86 


STUDIES  IN  SCIENCE 


How  do  the  ridges  compare  with  the  furrows  as  to 
width?  Look  at  two  or  three  different  species  of 
trees  until  you  are  certain  that  each  has  its  own 
bark  pattern.  Look  also  for  differences  in  shape 
and  branching.  Stand  at  some  distance  from  the 
trees  and  make  an  outline  sketch  of  the  different 
type  forms.  Consult  Figs.  17  and  18.  Compare  the 
forms  of  trees  standing  close  together  with  those  of 
the  same  species  standing  alone.  To  what  extent  are 


Fig.   18.     Tree  forms:    inverted  cone,  columnar,  and  conical. 

the  roots  visible  above  the  ground?     Compare  dif- 
ferent trees  with  reference  to  this  characteristic. 

Leaves.  Stand  under  a  trees  and  look  up.  Where 
are  the  leaves  most  numerous?  To  what  extent  do 
they  overlap?  Are  they  simple  or  compound?  Com- 
pare the  upper  and  under  sides.  What  are  the 
parts  of  one  leaf?  See  Fig.  19.  What  form  does 
the  petiole  take  where  it  is  attached  to  the  twig? 


TREE  STUDIES 


87 


How  are  the  leaves  arranged  on  the  stem  with  ref- 
erence to  each  other  ?  What  relation  can  you  see 
between  the  petiole  and  the  large  veins!  Hold  the 
leaf  between  you  and  the  light  to  see  how  numerous 
the  small  veins  are.  Study  the  leaves  on  one  twig 
and  note  differences  as  to 
size,  shape,  and  length  of 
petiole.  Can  you  see  any 
advantage  to  the  leaves  in 
the  different  sizes  of  the 
blades  and  the  different 
lengths  of  petioles  ?  If  you 
have  a  twig  indoors  lay  it 
down  upon  your  desk  allow- 
ing the  leaves  to  assume  a 
natural  position.  How  does 
this  help  you  to  solve  the 
problem? 

Compare  leaves  of  dif- 
ferent species  of  the  same 
family,  as  those  of  different 
maples,  oaks  or  elms,  and  determine  what  character- 
istics are  similar  and  what  are  different.  Make  a 
collection  of  all  the  different  types  of  leaves  you  can 
find. 

Watch  the  trees  frequently  for  a  number  of  weeks 
to  find  out  what  they  do  to  get  ready  for  the  winter 
season  of  inaction.  What  different  colors  do  you 


Fig.  19.  Parts  of  a  leaf:  a, 
Petiole;  b,  Blade;  c,  Midrib; 
d,  Veins;  e,  Margin. 


88 


STUDIES  IN  SCIENCE 


find?  WThat  color  is  most  prominent?  What  trees 
have  the  most  brilliant  reds?  Which  ones  are  chiefly 
yellow?  Which  dull  purple  or  brown?  When  the 
leaves  have  fallen,  examine  the 
spots  on  the  twigs  from  which 
they  dropped  and  try  to  decide 
what  caused  them  to  drop  off. 

Twigs.  Look  carefully  at  a 
twig  and  make  a  list  of  every- 
thing that  you  see.  This  study  is 
best  made  after  the  leaves  have 
fallen.  See  Fig.  20.  How  can  you 
tell  exactly  where  the  leaves  were 
located?  Describe  a  leaf  scar. 
Compare  the  scars  on  the  older 
parts  of  the  twigs  or  branch  with 
those  of  this  year. 

Classify  the  buds  as  to  position 
on  the  twigs  and  their  relation  to 
each  other.  How  do  they  differ 
as  to  shape  and  size  ?  What  will 
each  kind  of  bud  produce  ?  If  you 
do  not  know,  wait  until  spring  to 
solve  the  problem.  Examine  a 
bud  very  closely  and  describe 
what  you  see.  What  is  on  the  out- 

ticles;  d    Leaf  bud;  e,      gide|      The  insi<}e?      What  is  the 
Flower  bud. 


TREE  STUDIES  89 

value  of  the  scales,  the  downy  covering,  or  sticky 
secretion! 

How  can  you  tell  what  part  of  the  twig  grew  this 
year!  What  makes  this  ring  scar  I  How  many 
years'  growth  does  your  twig  represent? 

Compare  the  twigs  of  a  number  of  different  trees 
with  reference  to  the  length  of  growth  in  one  season, 
the  arrangement  of  buds,  and  the  shape  of  leaf  scars. 

Fruit  and  seed.  Make  a  list  of  all  the  trees  you 
can  find  that  retain  their  fruit  or  seeds  during  the 
fall  or  after  the  leaves  have  fallen.  Describe  the 
different  kinds  of  fruit.  How  many  of  them  have 
special  adaptations  for  dissemination?  Open  up  the 
fruit  in  each  case  and  find  the  seeds. 

Make  a  list  of  everything  you  have  discovered 
that  deciduous  trees  do  to  get  ready  for  the  winter 
rest  and  for  renewal  of  growth  in  the  spring. 

You  will  find  the  following  outline  helpful  in  keep- 
ing a  record  of  your  tree  studies.  Do  not  think  that 
every  item  must  be  put  in  with  your  first  observa- 
tion. You  may  have  to  wait  months  to  complete 
the  record. 

OUTLINE  FOR  TREE  STUDY 

1.     Name: 

2.  Shape: — conical,  broad  conical,  narrow  conical,  spherical,  col- 
umnar, inverted  cone. 

3.    Method  of  branching:  —  (a)   excurrent.     (Main  stem  may  be 


90  STUDIES  IN  SCIENCE 

traced  from  ground  to  top  of  tree) ;     (b)     deliquescent.     (Main  stem 
breaks  up  into  branches.) 

4.  Twigs: — erect,  drooping,  slender,  thick,  graceful,  stiff,  etc. 

5.  Trunk  or  bole: — color;  surface,  smooth,  rough,  scaly,  furrows 
or  fissures,  deep  or  shallow,  ridges  wide  or  narrow. 

6.  Leaves: — arrangement,  opposite  or  alternate;  simple  or  com- 
pound;, if  compound,  number  of  leaflets;  oddly  pinnate,  evenly  pin- 
nate;  special  characteristics;    shape,  color,  roughness,  smoothness, 
etc. 

7.  Flowers: — date  of  flowering,  kind:   (a)  perfect,  both  stamens 
and  pistil  in  one  flower;   (b)  staminate,  a  flower  with  stamens  and 
no  pistil;    (c)  pistillate,  one  with  pistil  and  no  stamens. 

8.  Fruit: — date  of  maturing,  kind.     Seeds: — kind. 

9.  Buds: — arrangement,    opposite    or    alternate,    shape,    color, 
scales. 

10.  Remarks: — value  of  tree  for  ornamental  purposes.  Other 
uses,  etc. 

Charts  and  booklets.  Make  a  set  of  tree  charts, 
or  booklets.  Each  individual  tree  species  repre- 
sented on  a  chart  or  page  should  contain  a  leaf,  the 
fruit,  seeds,  and  a  twig  in  winter  condition,  a  small 
bit  of  bark  and  when  possible  a  section  of  wood. 
Cardboard  or  any  stiff  paper  should  be  used,  and 
the  specimens  sewed  on  rather  than  pasted.  In 
regions  where  there  are  few  trees,  leaf  charts  may 
be  made.  Group  charts  or  pages  to  show  family 
relationship;  that  is,  put  together  all  the  oaks, 
maples,  pines,  etc. 

Discussion.  We  may  group  our  trees  into  broad- 
leaf  and  narrow-leaf  trees.  The  narrow  leaves  are 
usually  called  needles.  In  the  northern  and  central 
states  all  broad-leaf  trees  are  deciduous;  that  is,  they 


TREE  STUDIES 


91 


drop  all  of  their  leaves  each  year.  Almost  all  of  the 
needle-leaf  trees  are  evergreen.  A  few,  however, 
the  larch  and  cypress,  drop  their  leaves  in  the  fall. 
Some  of  the  broad-leaf  trees  in  the  South  retain  their 
leaves  during  the  winter. 

The  shape  of  a  tree  depends  largely  upon  the 
method  of  branching  and  the  number  and  character 
of  the  twigs.  A  tree  whose  trunk  breaks  up  into 


Sugar  or  Rock  Maple  Norway  Maple 

Fig.  21.     Sugar  or  Bock  Maple  and  Norway  Maple. 

a  number  of  branches  has  deliquescent  branching; 
one  whose  trunk  extends  up  through  the  crown  has 
excurrent  branching. 

Some  trees,  as  the  maple,  elm,  and  oak,  have  simple 
leaves.  Each  blade  is  in  one  piece,  although  the 
margin  may  be  notched  or  lobed.  Others  like  the 
walnut,  hickory  and  ash,  have  compound  leaves; 


92 


STUDIES  IN  SCIENCE 


that  is,  the  blade  is  divided  into  a  number  of  small 
leaves  called  leaflets.  If  the  leaf  has  an  odd  number 
of  leaflets  it  is  said  to  be  oddly  pinnate;  if  it  has 
an  even  number  it  is  evenly  pinnate. 

As  autumn  advances  you  notice  that  the  leaves 
change  color.  This  change  comes  because  the  leaves 
are  ceasing  to  work.  Their  chief  work  is  to  manu- 
facture starch  and  other 
foods.  As  this  work 
slowly  stops  the  green 
coloring  matter  changes 
to  yellow.  The  bright 
reds  and  the  dull 
purples  are  produced 
by  certain  chemical 
changes  that  take  place 
in  the  tissues  of  the 
dying  leaf.  Autumn 
coloration  then  simply 
tells  you  that  the  trees 


Fig.   22.     A  compound  leaf  show 
ing  seven  leaflets. 


have  shut  down  their  starch  factories  and  are  getting 
ready  for  the  season  of  rest.  You  sometimes  hear 
people  say  that  frost  is  the  cause  of  autumn  colora- 
tion and  the  dropping  of  the  leaves.  You  can 
readily  see  from  what  you  have  learned  that  this 
cannot  be  strictly  true.  The  fact  is  that  some 
years  the  leaves  are  a  brilliant  color  before  we 


TREE  STUDIES  93 

have  any  frost.  Early  cold  weather  accompanied 
by  frost  probably  causes  the  leaves  to  stop  their 
work  earlier  in  the  season,  and  that  is  all  that  frost 
has  to  do  with  it.  Sometimes  a  heavy  freeze  comes 
while  the  leaves  on  some  trees  are  still  active  and 
full  of  moisture.  In  that  case  they  are  simply  killed, 
which  is  shown  by  their  withering. 

The  dropping  of  leaves  comes,  too,  with  the  cessa- 
tion of  work.  As  you  looked  at  a  twig  from  which 
the  leaves  had  fallen,  you  found  that  no  wound  was 
left,  but  that  a  layer  of  skin  or  thin  bark  had  grown 
upon  the  twig  under  the  petiole.  This  layer  severs 
the  petiole  from  the  twig.  The  leaf  may  cling  for 
a  time  by  the  fibres,  but  a  slight  breeze,  the  weight 
of  raindrops,  or  even  its  own  weight  finally  takes  it 
off.  The  fibers  of  some  trees,  as  certain  oaks,  are  so 
firmly  attached  that  the  dry,  dead  leaves  remain  on 
the  twigs  all  winter. 

In  some  ways  the  buds  are  the  most  important 
things  that  are  found  on  the  twigs.  Do  you  know 
how  early  each  season  they  make  their  appearance? 
You  will  find  this  an  interesting  problem  to  solve 
by  observation  next  spring  and  summer. 

The  scales,  downy  coverings,  and  sticky  secretions 
protect  the  buds  from  mechanical  injuries,  but  their 
most  important  use  is  to  prevent  the  evaporation  of 
water.  During  the  winter  very  little  moisture  is 


94  STUDIES  IN  SCIENCE 

taken  into  the  tree  through  the  roots.  If  the  small 
leaves  and  flowers  in  the  buds  were  not  protected 
in  some  way,  they  would  dry  out  and  die. 

If  you  watch  the  buds  open  in  the  spring,  you  will 
find  that  usually  the  large  ones  on  the  twigs  pro- 
duce flowers,  while  the  smaller  ones  produce  a  twig 
with  leaves.  On  some  trees  the  leaf  and  flower  buds 
are  combined.  The  lateral  buds  produce  new  twigs 
and  afterwards  become  the  branches.  The  terminal 
buds  lengthen  the  branches.  When  the  buds  open 
the  scales  drop  leaving  the  ring  scars.  These  scars 
not  only  tell  you  where  the  buds  were  but  also  that 
the  scales  are  arranged  in  a  series  one  above  the 
other. 

The  dots  called  len'ti-cels  are  tiny  openings  in  the 
bark,  which  when  the  twig  is  young  allow  the  entrance 
of  air  and  probably  the  exit  of  waste  products  and 
water. 

Winter  study.  Do  not  stop  the  observation  of 
trees  during  the  winter.  This  is  one  of  the  best 
seasons  to  learn  the  typical  forms,  the  branching, 
color,  and  especially  the  twig  and  bud  characteristics. 
If  you  have  never  looked  closely  at  trees  during  this 
season,  you  will  be  surprised  to  find  how  individual, 
how  interesting,  and  how  beautiful  they  are. 


WINTER  STUDIES 

CHAPTER  V 
SOILS 

Material.  Soil  from  gardens,  fields  and  excava- 
tions; a  collection  of  pebbles,  gravel,  sand,  silt  and 
clay;  apparatus  described  in  connection  with  experi- 
ments. 

Examine  carefully  a  small  quantity  of  soil  that  has 
been  taken  from  a  cultivated  field  or  a  garden.  Write 
out  a  list  of  everything  that  you  find. 

Experiment.  Place  some  of  the  soil  in  a  large  iron 
spoon  and  hold  it  over  the  flame  of  an  alcohol  lamp 
or  gas  burner.  Heat  it,  stirring  occasionally.  What 
happens?  Set  it  away  to  cool  and  then  examine  it 
again.  What  changes  have  taken  place?  Is  the  color 
lighter  or  darker?  What  part  burned  up?  What  is 
the  material  that  is  left?  Before  you  try  to  answer 
fully  the  last  question  examine  a  small  portion  of 
sand,  silt  and  clay.  Look  at  each  with  a  hand  lens. 
Which  has  the  finest  particles?  What  do  you  find  in 
the  sand  that  is  not  present  in  the  silt  or  clay?  Take 
a  pinch  of  each  between  your  thumb  and  finger  and 
rub  them.  How  does  the  sand  feel?  The  silt?  The 

95 


96  STUDIES  IN  SCIENCE 

clay?  Silt  is  often  spoken  of  as  clay.  The  yellow 
clay  of  the  Middle  West  is  silt. 

Heat  a  small  portion  of  clay  and  of  silt  just  as  you 
did  the  garden  soil.  Describe  what  takes  place.  After 
they  have  cooled  compare  each  with  the  burned  gar- 
den soil.  Which  one  resembles  it  most?  Can  you 
decide  now  what  you  got  from  burning  the  garden 
soil? 

Explanation.  You  no  doubt  found  small  bits  of 
roots  and  other  parts  of  half -decayed  plants  in  your 
sample  of  soil.  When  you  heated  it  the  plant  parti- 
cles burned  up  and  you  had  left  what  may  be  called 
the  foundation  soil.  What  this  foundation  soil  is 
depends  wholly  upon  the  region  from  which  it  was 
taken.  It  may  be  almost  pure  sand,  pure  silt,  or  some 
kind  of  clay.  The  probabilities  are  that  it  is  a  mix- 
ture of  sand  and  silt  or  sand  and  clay.  In  any  case 
the  soil  mixture  including  the  part  that  burned  is 
called  loam.  If  it  has  a  large  per  cent  of  sand  it  is 
sandy  loam;  if  there  is  much  more  silt  than  sand  it 
is  silt  loan;  and  if  clay  is  the  most  prominent  part  it 
is  clay  loam. 

The  part  that  burned,  the  organic  matter,  is  called 
humus.  Leaf  mold  in  the  woods,  the  soft  decaying 
material  under  layers  of  pine  needles,  the  remains  of 
an  old  straw  stack,  or  well  rotted  stable  manure,  are 
all  types  of  humus. 


SOILS  97 

You  can  find  out  by  experiment  something  more 
about  the  different  kinds  of  soil. 

Experiment.  Pour  the  same  amount  of  water  into 
each  of  three  tumblers.  Stir  into  one  a  tablespoonful 
of  sand,  into  another  clay,  and  into  the  third  silt. 
Which  settles  to  the  bottom  first?  Keep  a  record  of 
the  time  that  it  takes  for  the  water  to  become  clear 
in  each  glass.  What  does  this  tell  you  about  the  size 
of  the  particles  of  each  kind  of  soil!  Which  will 
remain  suspended  longer  in  the  water,  coarse  or  fine 
particles  ? 

Experiment.  Put  a  spoonful  of  your  garden  loam 
into  a  glass  of  water  and  stir  as  before.  How  does  it 
behave?  After  it  has  all  settled,  look  through  the 
glass  to  determine  whether  or  not  the  soil  shows* 
any  layers  of  coarse  and  fine  material. 

Explanation.  These  experiments  show  that  differ- 
ent soils  differ  greatly  with  reference  to  the  size  of 
the  particles.  You  probably  found  that  the  sand 
settled  to  the  bottom  before  the  silt  or  clay.  This 
is  because  the  particles  are  larger  and  heavier.  Dif- 
ferent sands  vary;  some  are  coarse,  some  fine.  Silt 
is  much  finer  than  sand,  but  not  as  fine  as  clay.  Dif- 
ferent silts  and  clays  vary  just  as  sands  do.  Some 
are  very  fine,  others  are  coarse. 

If  your  garden  loam  is  a  mixture  of  sand  and  clay 
or  silt,  you  probably  found  that  it  had  settled  in 


98  STUDIES  IN  SCIENCE 

layers,  the  sand  in  the  bottom  and  the  clay  or  silt  on 
top.  You  probably  found,  too,  that  some  of  the 
humus  remained  floating  in  the  water  long  after  all 
the  rest  had  settled. 

Origin  of  soil.  What  is  the  origin  of  soil!  Per- 
haps you  have  already  found  out  something  about 
this  from  your  geography;  if  not,  you  can  think  out 
part  of  the  answer  for  yourself. 

Collect  from  the  bed  of  a  stream,  the  shore  of  a 
lake  or  wherever  you  can  find  them,  a  number  of 
pebbles. 

Examine  the  pebbles  you  have  brought  in.  Place 
into  groups  those  that  seem  to  be  of  the  same  kind 
of  rock.  How  many  different  groups  have  you?  Do 
you  find  any  that  seem  to  be  made  of  more  than  one 
kind  of  rock?  With  a  nail  or  other  sharp  instrument 
scratch  the  different  kinds.  What  do  you  determine 
as  to  their  relative  hardness? 

Compare  your  pebbles  as  to  shape.  Is  there  any 
way  to  account  for  the  fact  that  some  are  round 
while  others  are  flat? 

Formation  of  pebbles.  With  a  hammer  break  some 
of  the  larger  stones  into  small  pieces.  How  do  the 
pieces  differ  from  the  pebbles? 

Experiment.  Can  you  think  what  has  made  the 
pebbles  so  smooth?  Fill  a  pint  milk  bottle  about  one- 
third  full  of  the  broken  bits  of  rock.  Now  pour  in 


SOILS  99 

water  until  the  rock  fragments  are  covered.  Place  a 
cover  on  the  bottle  or  hold  your  hand  over  the  top 
and  shake  vigorously.  As  the  pieces  of  rock  strike 
against  each  other  what  happens?  Continue  shaking 
them,  off  and  on,  for  days.  When  you  allow  the  bot- 
tle to  stand  until  the  water  is  clear  what  do  you  find 
in  the  bottom? 

Explain  why  you  find  so  many  pebbles  along 
streams,  and  on  the  shores  of  lakes  and  rivers.  If 
you  should  follow  a  stream  to  its  source  in  hills  or 
mountains,  would  you  find  as  many  small,  smooth 
pebbles  and  stones  there?  Why? 

Experiment.  Other  agents  that  help  to  break  up 
rocks.  Break  up  a  piece  of  limestone  or  marble.  Put 
the  pieces  into  a  bottle.  Into  a  half  pint  of  water 
put  a  tablespoonful  of  hydrocholoric  acid  and  pour 
over  the  pieces  of  stone.  Shake  thoroughly.  Describe 
what  happens. 

Discussion.  From  your  observation  and  study  you 
have  probably  come  to  the  conclusion  that  pebbles, 
gravel,  sand,  silt  and  clay  are  all  forms  of  broken  and 
ground  up  rock.  Indeed,  if  you  go  back  far  enough 
in  the  history  of  the  earth  you  must  think  of  a  time 
ages  and  ages  ago  when  there  was  no  soil  on  the  earth, 
nothing  but  solid  rock,  wrinkled  and  jagged  with  here 
and  there  huge  broken  pieces.  Little  by  little  various 
agents  ground  up  the  solid  rock  into  finer  and  finer 


100  STUDIES  IN  SCIENCE 

particles.  One  of  the  chief  agents  that  helped  to  do 
this  was  changes  of  temperature.  When  rocks  are 
heated  by  the  sun  they  expand.  When  cooled  they 
contract.  If  the  contraction  takes  place  suddenly, 
the  rocks  are  likely  to  crack  open. 

Freezing  is  another  important  soil-making  agent. 
Water  from  rains  or  melting  snow  gets  into  cracks  and 
crevices  of  rocks  and  when  it  freezes  it  expands  and 
breaks  the  rocks.  In  the  same  way  our  soil  in  fields 
and  gardens  is  made  finer  during  the  winter  by  thaw- 
ing and  freezing.  We  have  already  found  by  experi- 
ment that  the  rubbing  together  of  stones  through  the 
action  of  water  is  an  important  soil-making  agency. 

If  you  were  to  visit  a  stream  whose  source  is  in 
mountainous  regions,  you  would  find  near  the  source 
large  pieces  of  rocks  that  have  been  broken  from  the 
hillsides  and  bluffs  and  have  fallen  into  the  stream. 
These  pieces  are  the  beginnings  of  pebbles.  They 
are  broken  into  smaller  and  smaller  pieces  by  tumb- 
ling over  each  other,  by  the  action  of  frost,  and  by 
rubbing  together  as  they  move  farther  down  the 
stream.  After  a  long,  long  time  the  rough  edges  are 
worn  off  and  nothing  is  left  but  smooth  stones  or 
pebbles.  The  worn  off  particles  settle  to  the  bottom 
and  form  the  sand  or  mud  in  the  bed  of  the  stream. 

The  pebbles  found  on  the  shores  of  lakes  and  seas 
are  made  by  the  dashing  of  the  waves  back  and  forth 


SOSXA''  i/       101 

on  the  beach.  The  pieces  of  rock  roll  against  each 
other  and  the  edges  are  worn  off.  Pebbles  found 
along  shores  are  usually  round,  while  those  in  streams 
are  flat. 

The  work  of  glaciers,  the  great  ice  sheets  that 
moved  slowly  over  a  great  part  of  our  country 
thousands  of  years  ago,  accounts  for  much  of  our 
fine  silt  and  clay.  The  great  boulders  and  pebbles 
that  we  find  scattered  here  and  there  over  the  prairies 
are  also  due  to  glaciers.  If  you  look  closely  you 
may  find  scratches  on  some  of  these  stones.  As  the 
glaciers  moved  slowly  over  the  land  they  picked  up 
pieces  of  broken  rock  and  pebbles  and  carried  them 
along.  Some  of  them  passed  over  other  rocks  and 
pebbles  and  left  deep  scars  on  them. 

Your  experiment  with  the  acid  and  limestone  shows 
how  rocks  may  be  dissolved  by  chemicals  carried  in 
solution  in  water.  Plants  themselves  aid  in  making 
soil.  Certain  plants  that  are  called  lichens  will  grow 
upon  solid  rock.  As  they  grow  they  give  out  an  acid 
that  eats  into  the  rock  slowly  softening  it  and  chang- 
ing it  into  fine  soil. 

Broken  up  rocks  alone  do  not  make  soil.  You  found 
in  the  soil  of  the  garden  and  fields  partially  decayed 
vegetation  or  humus.  Humus  is  an  essential  part  of 
soil  and  is  necessary  to  plant  life.  It  is  produced  by 
parts  of  plants  slowly  decaying  in  the  soil  where  little 


102  ^^SfJXDBj^JN  SCIENCE 

oxygen  can  reach  them.  It  may  be  increased  in  any 
cultivated  field  by  plowing  under  stubble,  corn  stalks, 
grasses,  clover,  etc.  Humus  is  dark  in  color,  so  a 
black  soil  usually  indicates  an  abundance  of  humus. 


CHAPTER  VI 

WATER  IN  SOIL 

Material.  Samples  of  the  different  kinds  of  soil 
studied  in  the  last  chapter;  five  straight  lamp  chim- 
neys; a  rack  or  jars  to  hold  them;  tumblers. 

Source  of  water  in  the  soil.  Water  in  the  soil  is 
quite  as  necessary  for  plant  growth  as  minerals  from 
the  rock  particles  and  the  humus.  Rain  is  the  source 
of  all  soil  water;  if  you  watch  the  rain  during  a 
shower  you  will  observe  that  some  of  it  runs  off  the 
ground,  some  stands  in  puddles,  and  some  sinks  into 
the  earth. 

Ground  water.  All  the  water  that  goes  into  the  earth 
is  called  ground  water. 

Experiment.  To  determine  what  becomes  of  the 
ground  water.  Place  a  layer  of  pebbles  in  the  bottom 
of  a  tumbler,  cover  with  a  piece  of  cloth  and  on  top 
of  this  place  dry  garden  soil  until  it  stands  within 
an  inch  of  the  top.  Firm  the  soil  by  striking  the 
glass  on  the  table.  Pour  some  water  on  the  soil  a 
little  at  a  time  and  watch  to  see  what  it  does.  Con- 
tinue to  pour  until  water  stands  in  the  spaces  among 

the  pebbles  in  the  bottom  of  the  glass. 

103 


104  STUDIES  IN  SCIENCE 

Explanation.  When  rain  falls  upon  the  ground  it 
does  just  what  the  water  in  the  glass  did.  It  perco- 
lates slowly  downward  through  the  soil  till  it  is 
stopped  by  solid  rock  or  by  a  layer  of  clay  or  by  soil 
already  full  of  water.  Now  if  rain  continues  the 
water  will  fill  all  the  spaces  among  the  tiny  particles 
of  soil  until  it  finally  stands  on  the  surface  of  the 
ground,  for,  while  you  cannot  see  them,  soil  is  made 
up  of  fine  particles.  Water  that  is  found  in  the 
spaces  among  the  particles  of  soil  is  called  free  water. 
Plants  do  not  use  free  water. 

The  level  at  which  free  water  stands  in  the  soil  is 
called  the  ground  water  level  or  the  water-table. 
Perhaps  you  noticed  when  you  poured  water  upon 
the  dry  soil  in  your  experiment  that  bubbles  of  air 
came  out  as  the  water  went  in.  When  the  spaces  are 
not  filled  with  water  they  are  full  of  air. 

Capillary  water.  Examine  some  soil  that  is  slightly 
moist.  This  does  not  contain  free  water. 

Experiment.  Where  is  the  water  in  this  moist  soil? 
Tie  a  piece  of  thin  cloth  loosely  over  a  tumbler;  place 
two  or  three  small,  smooth  pebbles  close  together 
on  the  top  of  the  cloth.  Pour  some  water  over  the 
pebbles  and  let  it  drain  down  into  the  tumbler.  Now 
examine  the  pebbles.  Describe  what  took  place. 
Where  is  the  water  in  relation  to  the  pebbles! 

Explanation.     The  water  that  remains  clinging  to 


WATER  IN  SOIL  105 

the  pebbles  is  called  film  water  because  it  forms  a  film 
around  the  pebbles.  In  the  same  way  moist  earth  has 
a  film  of  water  around  each  tiny  particle  of  soil. 
This  is  known  as  capillary  water.  It  is  this  water 
that  plants  use.  The  free  water  must  be  drained  off 
to  give  the  roots  a  chance  to  get  the  capillary  water. 

Experiment.  Drainage.  Tie  a  piece  of  cloth  firmly 
over  the  tops  of  each  of  five  lamp  chimneys.  Put 
sand  into  one,  clay  or  silt  in  another,  and  loam  in 
another.  In  the  fourth  put  a  mixture  of  half  sand 
and  half  humus,  either  well  rotted  manure  or  leaf 
mold.  Into  the  last  put  a  mixture  of  half  clay  and 
La  If  harnus.  Arrange  a  rack  for  the  chimneys  or 
stand  each  one  in  a  jar.  Measure  a  definite  amount 
of  water  and  pour  it  slowly  into  the  sand.  Note  the 
number  of  minutes  required  for  the  water  to  pass 
through  and  drip  into  a  dish  or  the  jar.  Keep  a 
record  of  the  amount  of  water  you  pour  in.  Do  the 
same  with  all  the  other  chimneys.  Measure  the 
amount  of  free  water  that  drips  from  each.  Through 
which  soil  does  the  water  drain  most  readily!  Which 
one  takes  longest  for  the  water  to  pass  through? 
Which  soil  retains  the  greater  amount  of  water? 
What  is  the  effect  of  putting  humus  into  sand?  Of 
putting  it  into  clay? 

Explanation.  Your  experiment  shows  that  water 
passes  rapidly  through  sand  but  slowly  through  silt 


106  STUDIES  IN  SCIENCE 

or  clay.  Humus  in  sand  makes  it  retain  more  water 
and  drain  less  rapidly,  while  humus  in  clay  has  the 
opposite  effect.  Humus  then  improves  both  of  these 
soils. 

What  method  is  used  in  your  neighborhood  to  drain 
the  soil?  If  you  live  in  the  country  find  out  how 
your  farm  is  drained.  You  may  find  an  open  ditch 
or  an  underdrain. 

Drainage  is  of  advantage  for  several  reasons: 
1.  The  ground  water  level  is  lowered  so  that  the 
roots  of  plants  go  deeper  into  the  ground.  A  deep 
root  system  is  of  value  to  plants  during  the  dry 
season.  2.  It  gives  an  opportunity  for  air  to  reach 
and  fill  the  spaces  near  the  surface,  and  plants  need 
air  as  well  as  water.  3.  A  well  drained  soil  warms 
earlier  in  the  spring.  Do  you  know  why!  A  soil 
full  of  water  uses  up  heat  in  evaporating  the  moisture. 

Underdrainage,  where  it  can  be  practiced,  is  more 
satisfactory  than  the  open  ditch.  It  does  not  waste 
land  since  the  soil  over  the  tile  may  be  cultivated. 
It  drains  to  a  greater  depth  and  thus  makes  it  pos- 
sible for  the  plants  to  produce  a  deeper  root  system. 
See  Fig.  23. 

The  value  of  drainage  is  not  generally  understood. 
Where  the  land  is  not  at  all  level,  or  where  the  soil 
to  a  considerable  depth  is  composed  of  sand  or  gravel, 
drainage  is  not  likely  to  be  important,  because  the 


WATER  IN  SOIL 


107 


excess  water  runs  away  over  the  surface  or  settles  to 
a  depth  below  the  level  of  ordinary  plant  roots. 

On  the  other  hand,  where  the  land  is  very  low,  or 
very  level  over  a  considerable  area,  the  soil  is  likely 
to  be  saturated  with  water  to  a  level  somewhere  near 
the  surface.  For  example,  if  one  digs  a  hole  he  usually 
has  not  to  go  down  very  far  before  he  finds  that  the 
water  flows  in  and  stands  at  a  certain  level  in  the 


Fig.  23.     Showing  one  important  effect  of  drainage. 

hole.     This  shows  the  level  at  which  the  soil  at  that 
particular  place  is  saturated  with  water. 

In  undrained  land  this  water  level  varies  in  distance 
below  the  surface  of  the  soil  according  to  whether  the 
season  is  dry  or  there  is  much  rainfall.  During  the 
wet  season  it  is  likely  to  be  very  near  the  surface, 
perhaps  not  more  than  six,  eight,  or  twelve  inches. 
See  line  a  in  Fig.  23.  Plant  roots  do  not  thrive  below 


108  STUDIES  IN  SCIENCE 

this  water  level,  because  they  cannot  get  air.  More- 
over, when  the  soil  is  thus  saturated  for  a  considerable 
length  of  time  it  is  cold  and  is  likely  to  become  sour. 
Plants  growing  on  soil  of  this  kind  do  not  thrive. 
They  commonly  look  weak  and  the  leaves  turn  yellow. 
Then  if  there  is  a  period  of  drought  the  water  level 
may  be  considerably  lowered  in  a  short  time.  See  line 
b  in  the  diagram.  In  such  a  case  the  plant  roots  are 
not  only  left  away  above  the  water  line,  but  the  soil 
is  likely  to  bake  and  harden. 

The  other  part  of  the  diagram  indicates  that  where 
the  soil  is  drained  the  water  level  is  likely  to  be  main- 
tained at  nearly  all  times  at  the  level  of  the  drain. 
See  line  c.  Under  these  conditions  the  plant  roots 
extend  themselves  far  enough  down  in  the  soil  to  get 
all  the  moisture  they  need.  In  addition  to  this  the 
soil  above  the  water  level  in  drained  land  never  bakes 
or  hardens ;  that  is,  it  is  always  open  and  porous.  The 
plant  roots  grow  more  freely  in  it  and  the  moisture  is 
drawn  upward  above  the  water  level  by  the  capillary 
action  in  the  soil  quite  uniformly  at  all  times. 

Irrigation.  You  may  live  in  a  region  where  irriga- 
tion is  necessary.  All  through  the  western  states 
there  are  large  tracts  where  the  annual  rainfall  is  not 
sufficient  for  the  growth  of  plants.  Here  water  is 
brought  from  mountain  streams  or  lakes  through 
tunnels  or  aqueducts.  Usually  small  ditches  several 


WATER  IN  SOIL  109 

rods  apart  extend  through  the  fields  or  orchards. 
The  owner  controls  the  supply  by  opening  a  sluice 
and  allowing  the  water  to  run  into  the  ditches  and 
flood  the  fields. 


CHAPTER  VII 

SOIL  WATER  AND  PLANTS 

Material.  Seeds  of  oats,  corn,  radishes  or  other 
plants;  plates  or  boxes,  a  growing  plant  in  a  pot. 

Experiment.  Root-hairs.  You  know  that  plants 
cannot  live  without  water  and  you  will  be  interested 
in  learning  how  they  get  water  from  the  soil.  Place 
some  seeds  of  radishes,  oats,  wheat,  or  corn  on  a  plate 
of  moist  sand  or  soil.  Press  them  slightly  into  the 
soil  but  do  not  cover.  Turn  a  plate  over  them  to  keep 
the  moisture  in.  Watch  them  from  day  to  day..  Do 
not  allow  the  soil  to  dry.  Describe  the  roots  and 
root-hairs.  On  what  part  of  the  roots  are  the  hairs 
most  numerous!  On  what  part  are  there  no  hairs? 
Place  one  of  the  plants  on  a  piece  of  paper  on  your 
desk  for  a  short  time.  What  happens  to  the  hairs? 
Watch  the  plants  for  several  days  to  see  whether  any 
of  the  hairs  wither  and  die  and  whether  new  ones 
continue  to  appear.  (Refer  to  Fig.  8,  page  33.) 

Explanation.  You  found  the  delicate  hairs  grow- 
ing all  around  the  young  roots.  If  these  roots  were 
covered  with  soil,  the  root-hairs  would  penetrate  the 
spaces  between  the  soil  particles  and  come  in  close 

no 


SOIL  WATER  AND  PLANTS  HI 

contact  with  the  films  of  water.  The  film  or  capil- 
lary water  passes  through  the  thin  walls  of  the  root- 
hairs.  You  may  think  this  a  slow  process  and  it  is, 
but  when  you  consider  the  thousands  of  root-hairs 
on  all  the  small  roots  of  the  growing  plants  you  realize 
that  together  they  can  take  in  a  vast  quantity  of 
water.  The  process  by  which  the  water  passes 
through  the  thin  membranes  of  the  root-hair  is  called 
osmosis.  The  same  process  takes  place  in  your  own 
body  when  digested  food  is  absorbed  by  tiny  capil- 
laries which  surround  the  digestive  tract,  and  is  car- 
ried into  the  blood  to  be  distributed  to  all  parts  of 
the  body. 

The  water  that  plants  take  into  their  roots  is  not 
pure  water  but  has  in  it  certain  minerals  that  the 
plants  use  in  their  growth. 

Experiment.  To  distinguish  soluble  and  insoluble 
substances. 

1.  Into  a  half  glass  of  warm  water  slowly  stir  some 
fine  salt.     Continue  to  put  in  salt  until  it  begins  to 
settle  to  the  bottom  of  the  glass.     What  became  of 
the  salt  that  disappeared!     Drain  off  the  clear  water, 
put  it  into  a  pan  and  place  it  on  a  stove  or  over 
an  alcohol  lamp  till  it  is  all  evaporated.    What  is  left 
in  the  pan!     How  is  salt  commonly  obtained!     Make 
the  same  experiment  with  sugar  and  saltpetre. 

2.  Into  a  half  cup  of  water  stir  some  chalk  dust, 


112  STUDIES  IN  SCIENCE 

lime,  or  sulphur.    Do  any  of  these  act  as  the  salt  and 
sugar  did?    How  do  you  account  for  the  difference? 

Explanation.  The  salt  disappeared  because  it  was 
dissolved  by  the  water  and  changed  into  a  liquid. 
The  chalk  or  sulphur  will  not  dissolve  in  water  so 
it  remains  in  the  solid  form.  A  substance  that  dis- 
solves as  the  salt  did  is  said  to  be  soluble  in  water. 
Chalk  and  sulphur  are  insoluble  in  water.  You  can 
see  from  this  that  all  soil  minerals  that  enter  the 
root-hairs  must  be  soluble  in  water. 

All  seed  plants  need  ten  different  elements  if  they 
are  to  grow  and  produce  fruit.  Seven  of  these  are 
obtained  from  the  soil.  They  are  nitrogen,  phos- 
phorus, potassium,  calcium,  sulphur,  iron  and  mag- 
nesium. The  last  three  are  so  abundant  in  soils  and 
are  used  in  such  small  quantities  that  we  do  not  need 
to  concern  ourselves  about  them.  Calcium  is  abund- 
ant in  most  soils  but  is  lacking  in  a  few  regions.  The 
first  three  elements,  nitrogen,  phosphorus,  and  potas- 
sium, are  not  abundant  in  most  soils  and  are  used 
in  comparatively  large  quantities;  hence  they  are 
frequently  lacking  in  fields  that  have  crops  growing 
in  them  year  after  year.  When  we  speak  of  "worn 
out  soil,"  we  usually  mean  that  it  lacks  one  or  two 
of  these  elements. 

Good  farmers  and  gardeners  try  to  keep  their  soil 
fertile  by  the  use  of  fertilizers,  by  plowing  under 


SOIL  WATER  AND  PLANTS  113 

plenty  of  vegetation  to  make  humus,  and  by  good  till- 
age to  insure  a  deep,  rich,  mellow  soil-home  for  the 
plants. 

The  constant  supply  of  water  and  mineral  food. 
How  to  keep  a  constant  supply  of  capillary  water 
for  the  growing  plants  in  regions  that  depend  entire- 
ly upon  rain  is  a  problem  of  much  interest. 

Experiment.  What  are  all  the  ways  in  which 
capillary  water  is  taken  from  a  field  or  garden  in 
which  plants  are  growing? 

Fill  a  tumbler  with  moist  soil.  Invert  over  it 
another  tumbler.  Set  it  aside  for  twenty-four  hours 
and  then  examine.  What  do  you  find  on  the  inverted 
glass!  Where  did  the  moisture  come  from? 

This  shows  that  moist  soil  is  constantly  losing 
some  of  its  moisture  by  evaporation.  You  know  also 
that  the  plant  itself  is  using  up  moisture.  If  this 
continues  for  days  and  there  is  no  rain,  the  soil  will 
become  dry  far  below  the  surface. 

Experiment.  Capillarity.  Tie  a  piece  of  cheese 
cloth  over  one  end  of  a  long  glass  tube,  open  at  both 
ends,  and  fill  it  with  dry  soil.  Stand  the  tube  in  a 
jar  containing  about  an  inch  of  water.  What  hap- 
pens? Leave  it  for  several  days  to  determine  how 
high  the  water  will  go  in  the  soil.  You  can  make 
some  other  experiments  to  illustrate  the  same  prin- 
ciple. Tie  a  piece  of  an  old  towel  to  a  pencil  and 


114  STUDIES  IN  SCIENCE 

let  the  free  end  dip  down  into  a  jar  which  contains  a 
small  amount  of  water.     What  takes  place? 

The  same  thing  takes  place  in  the  soil  and  in  the 
towel.  The  water  slowly  rises.  This  is  caused  by 
what  is  known  as  capillarity  or  capillary  attraction, 
and  always  occurs  when  liquids  come  in  contact  with 
fibrous  or  porous  materials.  The  ordinary  lamp  wick 
which  conveys  oil  from  the  bowl  of  the  lamp  to  the 
top  of  the  wick  is  a  good  example  of  capillary 
attraction. 

Experiment.  Capillarity  found  in  different  soils. 
Fill  several  glass  tubes  or  the  lamp  chimneys  used 
in  the  drainage  experiment  with  different  kinds  of 
soil.  Place  the  lower  ends  in  water,  and  determine 
which  soil  lifts  the  water  to  the  highest  point  by 
capillary  attraction. 

As  water  is  used  up  by  plants  in  the  fields,  more 
is  constantly  moving  upward  from  the  free  water 
below.  If  the  weather  is  very  warm,  much  of  the 
water  that  moves  upward  may  be  lost  to  the  plants 
by  evaporation,  so  another  problem  of  the  gardener 
and  farmer  is  how  to  prevent  this  loss. 

Experiment.  Conserving  soil  moisture.  Put  equal 
amounts  of  soil  into  two  pans  of  the  same  size.  Firm 
the  soil  by  gently  jarring  the  pans  upon  the  table. 
Pour  equal  amounts  of  water  over  each.  Weigh  each 
pan  and  set  them  side  by  side.  Thoroughly  stir  the 


SOIL  WATER  AND  PLANTS  115 

upper  inch  and  a  half  of  soil  in  one  pan  every  day 
keeping  the  layer  on  top  very  fine.  Leave  the  other 
pan  undisturbed.  Weigh  them  at  the  end  of  three 
or  four  days,  and  again  at  the  end  of  a  week.  Which 
one  has  lost  more  weight!  Explain  why  the  stirring 
of  the  soil  prevents  evaporation  of  water. 

As  long  as  the  soil  is  left  alone  the  water  moves  to 
the  surface  by  capillarity  and  evaporates.  Then 
cracks  are  likely  to  come  in  it  which  allow  the  air 
to  penetrate  to  quite  a  depth  and  aid  in  evaporating 
the  water.  The  stirring  of  the  soil  stops  the  flow  of 
water  to  the  surface.  It  is  like  breaking  off  the  ends 
of  tubes.  This  keeps  the  water  in  the  soil.  The  layer 
of  dry  soil  is  called  a  soil  mulch.  You  see  how 
important  it  is  to  cultivate  the  top  layer  of  soil  in 
your  garden  or  fields  during  hot  dry  weather. 

Experiments.  What  becomes  of  all  the  water  that 
plants  take  from  the  soil? 

(a)  Procure   a   small  plant   growing  in  a  flower 
pot.     Tie  a  piece  of  writing  paper  over  the  top  of 
the  pot.    To  do  this  slit  the  paper  to  the  center,  then 
cut  out  a  round  hole  just  the  size  of  the  plant  stem 
and  slip  the  paper  around  the  plant.     Place  a  glass 
jar  over  the  plant  and  set  it  in  the  window.    Look  at 
it  the  next  day.     What  has  happened?     Where  did 
the  moisture  come  from  that  settled  upon  the  glass? 

(b)  Allow   a  plant   growing  in   a  flower  pot   to 


116  STUDIES  IN  SCIENCE 

remain  a  number  of  days  without  water.  A  small 
coleus  or  foliage  plant  is  good  for  this  experiment. 
What  change  occurs  in  the  appearance  of  the  plant? 
Pour  water  over  the  soil  thoroughly  soaking  it.  Keep 
a  record  of  the  number  of  minutes  till  the  drooping 
leaves  and  stems  revive.  What  now  holds  the  plant 
rigid  and  erect? 

Explanation.  The  moisture  that  gathered  upon 
the  glass  in  experiment  (a)  came  from  the  leaves  and 
stems  of  the  plant.  It  was  given  out  in  the  form  of 
vapor  and  condensed  upon  the  cool  glass.  It  could 
not  come  from  the  soil  because  that  was  covered  up, 
All  living,  working  plants  are  constantly  evaporating 
water.  The  process  is  called  transpiration. 

The  second  experiment  tells  you  that  one  use  of 
water  in  growing  plants  is  to  keep  them  rigid  and 
erect.  When  too  much  water  is  evaporated  com- 
pared to  the  amount  taken  in  the  plant  wilts. 

In  order  that  plants  may  obtain  from  the  soil  all 
the  water  and  minerals  they  require  for  their  work, 
farmers  and  gardeners  must  treat  the  soil  so  that 
it  will  produce  the  best  yield  of  crops  now,  and  at 
the  same  time  insure  the  production  of  good  crops 
in  all  the  years  to  come.  To  do  this  a  number  of 
things  are  necessary: 

1.  Tillage.  This  includes  two  processes,  breaking 
or  plowing,  disking  and  harrowing,  in  preparation 


SOIL  WATER  AND  PLANTS  117 

for  the  seed,  and  cultivation  when  the  crop  is  grow- 
ing. Good  tillage  increases  the  depth  of  the  soil. 
This  means  that  the  plowing  must  be  deep.  If  only 
the  upper  three  or  four  inches  are  turned  over  the 
surface  of  the  soil  will  soon  become  depleted  of  its 
mineral  plant-foods.  Moreover,  the  lower  layer  of 
soil  will  become  packed  and  sour  and  utterly  unfit 
for  the  plant  roots.  Tillage  also  aids  in  the  saving 
of  moisture.  How?  Think  of  your  experiment  with 
soil  mulch.  It  also  loosens  the  soil  so  that  it  will 
hold  more  air  and  allow  better  ventilation.  It  kills 
out  the  weeds  and  thus  prevents  a  loss  of  plant-foods 
to  the  crop.  It  turns  under  vegetation  and  thus 
increases  the  amount  of  humus  in  the  soil. 

2.  Drainage.    We  have  already  seen  that  drainage 
is  of  advantage  in  lowering  the  ground  water  level 
and  in  keeping  the  soil  surface  open  for  the  entrance 
of  air. 

3.  Rotation  of  crops.     Agriculturists  are  coming  to 
believe  more  and  more  that  growing  the  same  kind  of 
crop  in  a  field  year  after  year  will  result  in  absolute 
ruin  to  the  soil.     One  reason  for  this  is  that  certain 
crops  use  more  of  one  kind  of  plant-food  in  the  soil 
than  others  do.     After  a  number  of  years  the  soil 
is  so  lacking  in  this  particular  compound  that  it  is 
difficult  to  grow  any  kind  of  a  crop  on  it. 

When  legumes   are   rotated   with   other   crops   the 


118  STUDIES  IN  SCIENCE 

supply  of  nitrogen  is  kept  constant  in  the  soil.  Bota- 
tion  also  gives  an  opportunity  to  kill  out  weeds  that 
are  likely  to  persist  if  the  same  crop  is  grown  year 
after  year.  It  also  helps  to  get  rid  of  certain  insect 
pests.  Every  farmer  must  settle  for  himself  the  crops 
that  are  to  be  rotated;  but  he  should  adopt  a  definite 
system  of  plant  rotation  and  follow  it  in  regular 
order  year  after  year.  A  common  rotation  in  the 
corn  belt  is  oats,  clover,  corn. 

4.  Fertilizer's.  Fertilizers  are  of  two  kinds,  nat^ 
ural  and  commercial.  Of  the  first  barnyard  manure 
is  the  best.  It  not  only  increases  the  humus  of  the 
soil,  but  it  is  rich  in  the  three  elements  that  soil  needs, 
nitrogen,  phosphorus  and  potassium.  Green  manure 
is  another  natural  fertilizer.  This  means  the  plowing 
under  of  green  crops.  All  the  legumes  as  clovers, 
cow-peas  and  alfalfa,  when  plowed  into  the  soil  are 
green  manures.  Bye  and  rape  are  also  used  for  this 
purpose. 

Commercial  fertilizers,  as  the  name  implies,  are 
materials  that  are  bought  and  put  in  the  soil.  To 
supply  phosphorus,  bone-meal  and  rock  phosphate 
are  used.  For  nitrogen,  Chile  saltpetre  (nitrate  of 
soda),  dried  blood,  and  sulphate  of  ammonia  are 
used.  For  potassium,  different  forms  of  potash  are 
used. 

If  calcium  is  lacking  in  soil  lime  should  be  used.     It 


SOIL  WATER  AND  PLANTS  119 

is  also  used  to  sweeten  sour  soil.  When  soils  become 
sour,  the  bacteria  cease  to  change  the  organic  material 
into  humus.  Plants  do  not  thrive  well  in  sour  soil. 
Any  soil  that  has  been  used  for  a  long  period  of 
years  is  likely  to  become  sour  and  is  improved  by 
an  application  of  lime. 

Look  up  carefully  what  methods  of  rotation  are 
practiced  in  your  community;  also  what  special  means 
are  taken  to  maintain  the  fertility  of  the  soil. 


CHAPTER   VIII 

THE  WORK  OF  PLANTS 

Materials.  Potatoes,  grains  of  corn,  flour,  oat- 
meal, corn-starch,  seeds  of  sunflower,  cotton,  flax, 
squash  or  pumpkin,  solution  or  tincture  of  iodine. 

Plants  use  some,  of  the  water  that  they  obtain  from 
the  soil  in  the  manufacture  of  food  and  other 
products. 

Experiments.  What  foods  and  products  do  plants 
manufacture?  Scrape  as  fine  as  possible  one  or  two 
potatoes.  Place  the  scrapings  in  a  tumbler  of  water, 
stir  thoroughly  two  or  three  times,  and  allow  to 
settle.  Examine  next  day.  What  do  you  find  in 
the  bottom  of  the  tumbler?  Drain  off  all  the  water 
and  potato  pulp,  leaving  nothing  but  the  starchy 
looking  mass  in  the  bottom.  Boil  some  water  over 
the  alcohol  lamp  and  pour  a  little  of  this  into  the 
tumbler,  stirring  until  the  mixture  thickens.  This 
resembles  ordinary  laundry  starch. 

There  is  a  chemical  test,  however,  that  will  prove 
beyond  doubt  that  you  have  starch  in  the  tumbler. 
Place  a  small  quantity  of  the  cooked  starch  on  a  plate 
or  saucer,  and  then  put  two  or  three  drops  of  iodine 

120 


THE  WORK  OF  PLANTS  121 

on  it.  What  is  the  effect  of  iodine  on  the  substance? 
The  blue  color  indicates  the  presence  of  starch.  The 
darker  the  blue  the  more  starch  there  is  present. 
Sometimes  it  is  almost  black.  Place  a  drop  of  iodine 
on  a  slice  of  raw  potato.  Does  it  show  as  much 
starch  as  that  which  is  cooked?  The  reason  the  lat- 
ter shows  more  starch  is  that  the  boiling  water  causes 
the  walls  of  the  starch  granules  to  burst  open  and 
the  iodine  can  act  more  readily  upon  the  starch. 

Pour  a  little  boiling  water  over  some  flour  and 
test  it  for  starch.  Make  the  same  experiment  with 
corn-meal,  oatmeal  and  corn-starch. 

Soak  some  grains  of  corn  for  forty-eight  hours,  or 
for  an  hour  in  hot  water.  At  the  pointed  end  of  the 
grain  find  the  tip  cap.  Remove  this.  The  cap  may 
be  lacking  on  some  grains,  having  been  left  on  the 
cob.  With  a  knife  or  pin  remove  the  hull.  You  will 
see  that  the  grain  under  the  hull  is  covered  with  a 
thin,  smooth  material  that  with  care  may  be  scraped 
off  with  a  knife.  This  is  called  horny  gluten.  Now 
dig  out  the  germ  or  embryo.  This  is  the  light  gray, 
oval  shaped  portion  that  fills  up  the  groove  in  the 
soaked  grain. 

Split  open  the  remaining  part  of  the  grain.  How 
many  kinds  of  material  are  left?  Place  by  itself  the 
white  granular  material  found  near  the  crown  of 
the  grain.  Add  to  it  the  same  kind  of  material  found 


122  STUDIES  IN  SCIENCE 

near  the  tip.  Put  the  hard,  solid  looking  substance 
in  another  pile.  You  now  have  six  different  sub- 
stances found  in  your  grain  of  corn.  Test  each  of 
these  with  iodine  as  you  did  your  potato  starch  and 
flour.  It  is  best  to  crush  them  as  much  as  possible 
before  putting  on  the  hot  water.  What  part  shows 
the  most  starch!  It  is  probable  that  the  soft  granular 
part  will  turn  the  darkest  blue.  This  part  is  known 
as  crown  starch.  The  solid,  hard  part,  if  thoroughly 
boiled,  will  show  some  starch.  This  is  called  horny 
starch.  What  parts  do  not  contain  starch!  This 
means,  of  course,  that  there  must  be  some  substances 
other  than  starch  in  the  grain  of  corn. 

Eemove  some  fresh  embryos  from  soaked  grains 
and  crush  them  on  a  sheet  of  white  writing  paper. 
Hold  the  paper  between  you  and  the  light.  What  do 
you  see!  The  grease  spot  indicates  the  presence  of 
oil  or  fat.  Test  other  seeds  in  this  way  for  oil,  such 
as  sunflower,  squash,  pumpkin,  flaxseed,  etc. 

Put  a  small  pinch  of  each  of  the  following  on  a  sheet 
of  paper;  flour,  corn-meal,  any  cereal  breakfast  food, 
buckwheat,  and  ground  coffee.  Place  the  sheet  in  a 
hot  oven  and  keep  it  there  a  few  minutes.  What 
evidence  is  there  that  these  things  contain  oil!  Name 
some  plants  whose  seeds  contain  so  large  a  percentage 
of  oil  that  it  is  extracted  and  used  for  commercial 
purposes. 


THE  WORK  OF  PLANTS  123 

Discussion.  Besides  starch  and  oil,  plants  contain 
other  substances. 

The  embryo  of  the  corn  is  composed  largely  of  pro- 
tein. Another  substance  in  plants  is  sugar.  A  sweet 
potato  tastes  sweeter  than  a  white  potato  because  it 
contains  more  sugar.  Name  other  plants  that  have 
sugar  in  them.  From  what  plants  is  the  sugar  of 
commerce  obtained!  All  starch  found  in  plants  is 
changed  into  sugar  before  it  can  be  absorbed  by 
plants  or  animals.  Starch  is  insoluble  in  water,  and 
all  substances  absorbed  by  living  bodies  must  be 
soluble. 

The  corn  hulls  are  composed  chiefly  of  a  substance 
called  cellulose.  Cellulose  is  found  in  all  plants 
It  is  the  material  that  gives  strength  and  firmness 
to  the  different  parts.  It  is  found  in  the  cell-walls, 
in  fibers  of  stems,  roots,  and  leaves,  as  well  as  in 
fruits  and  seeds.  It  is  harder  and  thicker  in  some 
parts  of  the  plant,  as  in  the  stems,  husks  and  roots, 
than  in  others.  The  fibers  of  cotton,  hemp,  and  flax 
are  made  chiefly  of  cellulose.  Soak  some  newspapers 
or  writing  paper  in  water  till  all  the  sizing  is  washed 
out.  The  pulp  that  remains  is  almost  pure  cellulose. 
Much  of  our  paper  is  made  from  wood  pulp;  that  is, 
from  the  cellulose  of  the  woody  stems  of  trees. 

Where  do  the  plants  get  all  of  these  substances? 
They  manufacture  them.    All  plants  that  have  green 


124  STUDIES  IN  SCIENCE 

leaves  or  green  coloring  matter  in  any  part  manu- 
facture starch,  sugar  and  other  products. 

You  may  think  of  plants,  then,  as  factories,  with 
machinery,  power,  and  raw  materials.  The  raw 
materials  are  found  in  the  air,  soil,  and  soil-water 
about  the  plant.  They  are  found  in  the  form  of 
chemical  compounds  which  the  plants  take  in  and 
use.  You  may  not  know  what  a  compound  is.  Water 
is  an  excellent  example.  It  is  formed  by  the  union 
of  two  elements,  oxygen  and  hydrogen.  Both  of 
these  are  invisible  gases  which  do  not  at  all  resemble 
water.  An  element  is  a  substance  that  so  far  as 
chemists  know  cannot  be  separated  into  other  sub- 
stances. There  are  between  seventy  and  eighty  ele- 
ments known.  All  other  things  in  the  world  are 
compounds,  formed  by  the  union  of  two  or  more  ele- 
ments. Just  to  mix  elements  together  will  not  make 
a  compound.  They  must  unite  in  definite  proportions. 
In  order  to  understand  what  we  mean  by  this  you 
must  know  that  everything  in  the  world  is  made  up 
of  very  small  particles  called  molecules.  The  mole- 
cules are  so  small  that  they  cannot  be  seen  by  the 
most  powerful  microscope.  Each  molecule  is  made  up 
of  still  smaller  particles  called  atoms.  Now,  when  a 
chemical  union  takes  place  a  certain  number  of  atoms 
of  one  element  unite  with  a  certain  number  of  atoms 
of  another  element  or  elements  and  make  a  molecule 


THE  WORK  OF  PLANTS  125 

of  a  new  substance  which  is  a  compound.  In  water 
two  atoms  of  hydrogen  unite  with  one  atom  of  oxygen ; 
hence  we  use  the  symbol  H20  to  stand  for  water. 

Chemical  unions  are  taking  place  constantly  in  the 
world  of  nature.  In  plants,  chemical  combinations 
take  place  which  result  in  the  plant  products  you 
have  found.  Starch  is  a  combination  of  oxygen, 
hydrogen  and  carbon.  The  symbols  for  these  elements 
are  0,  H  and  C  respectively.  Proteid  is  a  combina- 
tion of  carbon,  hydrogen  and  oxygen,  with  nitrogen, 
sulphur,  phosphorus,  and  often  other  elements. 

The  plant  gets  its  oxygen  and  hydrogen  from  the 
water  which  it  absorbs  through  its  root-hairs.  It 
gets  carbon  from  the  air,  not  as  an  element  but  the 
compound  that  you  know,  carbon  dioxide.  Its  symbol 
is  C02.  This  tells  you  that  one  molecule  of  carbon 
dioxide  is  made  by  the  union  of  one  atom  of  C  and 
two  of  0. 

The  work  of  manufacturing  starch  takes  place  in 
the  leaves  or  other  green  parts  of  plants. 

Examine  a  leaf  of  any  plant.  Hold  the  leaf  between 
you  and  the  light.  What  do  yon  see  in  it?  How  are 
the  veins  arranged  in  a  bean  leaf,  maple,  sunflower? 
These  are  net-veined  leaves.  How  are  the  veins 
arranged  in  a  corn  leaf?  In  grass?  These  are  parallel 
veins.  What  is  the  use  of  the  veins?  One  apparent 
use  is  to  hold  the  blade  spread  out  to  the  light. 


126 


STUDIES  IN  SCIENCE 


Place  a  twig  with  growing  leaves  in  a  tumbler  of 
water  colored  with  red  ink.  After  twenty-four  hours 
examine  the  petiole  and  the  veins.  The  red  ink  in  the 
veins  tells  you  that  they  carry  water  to  all  parts  of 
the  leaf. 

Procure  a  thick  leaf,  as  live-for-ever,  tulip,  or  hepat- 


Fig.    24.      Cross   section   of   a   leaf,    showing   cell   walls,   chlorophyll 
bodies,  and  stomata,  or  breathing  pores. 

ica,  and  peel  off  a  little  of  the  skin  or  epidermis. 
You  can  remove  a  little  of  the  covering  from  a  thin 
leaf,  enough  to  see  that  the  entire  leaf  is  covered 
with  a  thin,  almost  transparent  skin.  What  is  under 
the  skin!  This  green  granular  mass  is  largely  made 
up  of  a  substance  called  chlorophyll. 

If  you  could  see  a  cross-section  of  a  leaf  highly 
magnified  you  would  find  it  built  up  of  cells.     Each 


THE  WORK  OF  PLANTS  127 

cell  lias  a  thin  wall,  contains  green,  roundish  bodies 
called  chlorophyll  bodies,  and  a  mass  of  colorless 
protoplasm.  These  form  the  machinery  that  manu- 
facture plant-food.  But  just  as  any  machinery  must 
have  power  to  make  it  run,  so  must  the  machinery 
of  the  leaf.  What  is  the  power? 

Experiment.*  Fill  a  box  or  dinner  plate  with  soil 
and  sow  some  oats  or  wheat  seeds.  After  the  grains 
have  sprouted  cover  one-half  the  plants  with  a  box 
or  tin  can.  Give  all  the  plants  the  same  amount  of 
water.  After  a  week  compare  the  plants  grown  under 
cover  with  those  grown  in  the  light.  What  do  the 
former  lack?  What  is  your  conclusion  as  to  the  abil- 
ity of  the  plants  to  make  chlorophyll  without  the  aid 
of  light? 

Discussion.  Eecall  the  color  of  grass  that  has  been 
covered  with  a  board,  or  the  color  of  potato  sprouts  in 
a  cellar.  Without  light  plants  cannot  make  chlorophyll, 
and  without  chlorophyll  no  starch  can  be  made.  The 
light  is  the  power  that  runs  the  machinery,  but  the 
chlorophyll  is  the  connecting  link  between  the  power 
and  the  machine.  In  some  way  it  succeeds  in  bring- 
ing them  together  so  that  they  are  able  to  carry  on 
their  work. 

You  remember  that  starch  is  made  out  of  oxygen 
and  hydrogen  from  water  and  carbon  from  air,  and 

*This  experiment  should  be  started  a  week  before  time  for  the 

lesson. 


128  STUDIES  IN  SCIENCE 

that  proteids  contain  these  three  elements  with  the 
addition  of  nitrogen,  sulphur,  phosphorus,  etc.,  which 
come  from  the  soil. 

The  leaves  take  in  carbon  dioxide  through  their 
stomata,  which  are  small  openings  in  the  epidermis. 
What  must  be  done  with  this  compound  before  the 
plant  can  use  the  carbon?  It  must  be  separated  into 
its  elements,  oxygen  and  carbon.  The  protoplasm 
decomposes  the  carbon  dioxide  and  uses  the  carbon. 
It  throws  the  oxygen  back  into  the  air.  Therefore, 
when  a  plant  is  actively  engaged  in  manufacturing 
starch  it  is  taking  carbon  dioxide  from  the  air  and 
giving  out  oxygen.  Why  cannot  this  process  be  car- 
ried on  during  the  night? 

What  do  the  plants  do  with  the  starch,  proteids, 
and  oils  that  they  make?  The  starch,  by  a  process 
something  like  digestion  in  our  bodies,  is  changed 
into  sugar,  and  this  and  the  other  foods  are  con- 
veyed in  liquid  form  from  the  leaves  to  all  parts 
of  the  plants,  where  they  are  used  in  the  growth  of 
these  parts. 

Do  plants  grow  at  night?  Measure  some  of  your 
corn  or  other  plants  at  night  and  again  in  the  morn- 
ing and  see  how  much  they  have  grown.  While  plants 
cannot  make  food  at  night,  they  can  use  the  food 
they  have  made  during  the  day  for  growth  during  the 
night.  Some  of  the  food  that  is  made  is  not  used  at 


THE  WORK  OF  PLANTS  129 

once  but  is  stored  away  for  future  use  in  roots,  stems 
and  seeds. 

Plants  need  something  besides  food  in  order  to  live 
and  grow.  They  are  like  animals  in  this  respect. 
They  must  have  air  to  breathe  as  well  as  food  to 
eat.  They  cannot  live  without  oxygen  any  more  than 
you  can.  They  carry  on  respiration  at  all  times  just 
as  you  do.  Not  only  the  leaves  but  the  stems  and 
roots  need  oxygen.  The  oxygen  is  taken  into  the 
cells  and  unites  with  the  carbon  and  other  elements 
giving  the  plant  its  energy.  Waste  products,  C02 
and  moisture  are  thrown  out  into  the  air. 

You  must  not  confuse  the  two  great  processes  that 
plants  perform.  In  making  starch  plants  take  C02 
from  the  air  and  give  out  oxygen.  In  respiration 
they  take  oxygen  from  the  air  and  give  out  C02. 
The  fact  is  that  much  more  C02  is  used  in  the  manu- 
facture of  food  than  oxygen  in  the  process  of  respira- 
tion, so  that  actively  working  plants  give  out  much 
more  oxygen  than  they  take  in.  These  two  processes 
go  on  at  the  same  time  during  daylight  just  as  diges- 
tion and  breathing  go  on  in  your  body  without  inter- 
fering with  each  other. 


CHAPTER  IX 

FOOD  AND  HEALTH 

The  foods  that  plants  make  feed  many  of  the  ani- 
mals of  the  world  including  man.  Since  this  is  true 
you  will  readily  see  why  the  human  body  is  com- 
posed of  precisely  the  same  elements  that  plants  use 
in  their  food. 

Classes  of  food.  We  group  foods  according  to  the 
elements  they  contain  as  follows :  (1)  carbohydrates, 
which  are  starches  and  sugars.  The  term  tells  you 
that  the  elements  composing  them  are  carbon,  hydro- 
gen and  oxygen.  A  chemical  compound  whose  name 
ends  in  the  syllable  ate  always  has  oxygen  as  one  of 
its  elements.  (2)  Proteids,  which  contain  carbon, 
oxygen,  hydrogen,  nitrogen,  sulphur,  and  phosphorus. 
(3)  Fats,  which  are  composed  of  carbon,  oxygen,  and 
hydrogen,  but  these  elements  are  combined  in  different 
proportions  from  those  in  starch. 

Carbohydrates.  Make  a  list  of  all  the  sources  of 
starch  that  you  know.  Do  the  same  for  sugar.  You 
will  find  that  you  have  a  long  list.  All  the  cereals, 
as  wheat,  corn,  oats,  rice,  etc.,  and  the  vegetables,  as 
potatoes,  sweet  potatoes,  and  fruits,  have  starch  or 

130 


FOOD  AND  HEALTH  131 

sugar  as  a  large  part  of  their  composition.  The  chief 
value  of  carbohydrates  in  your  body  is  to  produce 
heat  and  energy.  From  your  study  of  oxidation  you 
know  that  this  process  takes  place  in  the  cells  of 
your  body. 

Proteids.  All  grains,  especially  their  embryos,  con- 
tain some  proteid.  Beans  and  peas  have  a  larger 
percentage  of  proteid  than  other  vegetables.  All 
other  vegetables  and  fruits  have  small  amounts.  Most 
of  the  proteid  foods  are  obtained  from  animals.  All 
lean  meat  is  largely  proteid.  The  white  of  egg,  milk, 
cheese  and  fish  are  all  proteid  foods.  Proteid  is  the 
tissue  builder  of  the  body.  It  alone  contains  nitro- 
gen, the  element  which  is  necessary  in  the  making  of 
protoplasm.  There  can  be  no  building  of  new  cells 
or  repairing  of  old  ones  without  proteid.  The  mus- 
cles and  other  organs  are  constantly  wearing  out  and 
must  have  this  kind  of  food  to  replace  them. 

Fats.  Make  a  list  of  the  sources  of  fats  or  oils  and 
the  foods  in  which  these  are  found.  You  probably 
have  in  your  list  fats  of  animals  and  butter  fat  from 
milk,  as  well  as  vegetable  oils  from  cotton  seed,  olive 
seeds,  corn,  etc.  Fats  are  heat  making  foods  and  like 
carbohydrates  they  produce  energy.  Fat  which  is 
not  used  at  once  is  stored  in  the  body  for  future  use. 
During  an  illness  people  become  thin  and  wasted  be- 
cause their  bodies  have  had  to  use  up  all  the  surplus 


132  STUDIES  IN  SCIENCE 

store  of  fat.  Now  since  each  of  the  three  great  classes 
of  foods,  proteids,  fats  and  carbohydrates,  has  its 
special  use  in  the  body,  you  can  see  that  we  must  have 
some  of  each  of  these  foods  daily  in  order  to  keep  the 
body  in  good  condition.  Some  people  eat  too  much  pro- 
teid,  others  not  enough.  Too  much  proteid  may 
cause  diseases  of  the  kidneys,  because  these  are  the 
organs  that  get  rid  of  the  waste  from  nitrogenous 
foods.  Too  much  fat  and  carbohydrate  may  result  in 
the  storing  up  of  so  much  fat  that  it  is  injurious  to 
the  body. 

Cooking.  Most  foods  must  be  properly  cooked  in 
order  to  be  wholesome.  Cooking  produces  chemical 
changes  in  many  foods  and  gives  them  a  better  flavor. 
In  most  cases  it  makes  foods  easier  to  digest  and 
helps  to  kill  off  dangerous  bacteria  that  may  be  in 
them.  The  method  of  cooking  has  much  to  do  with 
the  wholesomeness  of  foods.  Roasting  or  baking 
meat  is  much  better  than  frying.  Few  vegetables, 
even  potatoes,  should  be  fried ;  instead  they  should  be 
baked,  creamed  or  scalloped.  Fried  foods  are  the 
cause  of  many  cases  of  indigestion  and  poor  health, 
because,  in  the  process  of  frying,  the  food  becomes 
coated  with  a  hard  layer  of  fat  which  must  be  dis- 
solved before  digestion  can  take  place.  Starchy 
foods  should  be,  cooked  thoroughly  so  that  the  grains 
of  starch  will  be  whollv  softened.  Proteids  should 


FOOD  AND  HEALTH 


133 


as  a  rule  be  cooked  slowly  and  should  not  be  over- 
done. 

Digestion.  Foods  to  be  of  value  in  the  body  must 
be  changed  into  liquid  forms  so  that  they  may  be 
taken  into  the  blood  and  carried  to  all  parts  of  the 
body.  This  process  is  called 
digestion.  It  begins  in  the 
mouth  where  the  teeth  break 
up  solid  particles  into  small 
bits.  Besides  this  mechanical 
change  in  the  mouth,  the  saliva 
acts  chemically  upon  starch 
changing  it  to  sugar.  When  the 
food  reaches  the  stomach  a 
fluid  called  gastric  juice  is 
poured  upon  it.  This  acts 
chemically  upon  the  proteids 
changing  them  to  another  sub-  Fig.  25.  The  digestive 

mi  tract:     A,  Mouth:  B.  Phar- 

stance    called    peptones.      The     ynx;  c,  Esophagus;  D,  Dia- 
food  then  passes  on  into  the     phragm;   E'   Stomach;   F' 


small   intestine   where   several 


Small  intestine;  G  and  H, 
Colon;  I,  Eectum;  J,  Ap- 
pendix. Transverse  colon 

other  juices  act  upon  it  to  finish  is  cut  out- 
the  digestion.  These  are  the  pancreatic  juice,  which 
comes  into  the  intestine  from  the  pancreas,  the  bile, 
which  comes  from  the  liver,  and  some  juices  that  pour 
out  of  the  walls  of  the  intestine.  By  the  time  these  have 
acted  upon  the  foods,  the  starches  are  all  in  the  form 


134 


STUDIES  IN  SCIENCE 


of  liquid  sugar,  the  fats  are  broken  up  into  tiny  drop- 
lets, and  the  proteids  have  all  been  changed  to  pep- 
tones. The  digested  food  is  now  in  a  condition  to  be 
absorbed  into  the  blood. 

The  lining  of  the  small  intestine  is  thickly  covered 

with  tiny  finger-like  projec- 
tions called  villi,  about  as 
close  together  as  the  nap  on 
felt  or  velvet.  In  each  villus 
is  a  little  tube  called  a  lacteal 
which  takes  up  the  fat  drop- 
lets. There  are  also  tiny 
blood  tubes  in  the  villi  which 
take  up  the  sugars  and  pep- 
tones. The  process  by  which 
these  liquid  foods  enter  the 
blood  is  precisely  the  same 
as  that  by  which  the  soil- 
water  enters  the  root-hairs 
of  plants,  and  is  called 
osmosis. 

The  fats  are  carried  into  a 
large  tube  called  the  thoracic  duct.  This  empties  into 
a  vein  near  the  collar  bone,  and  this  in  turn  empties 
into  a  large  vein  which  enters  the  right  auricle  of  the 
heart.  The  sugar  and  peptones  pass  into  the  blood  of 
a  large  vein  which  empties  first  into  the  liver.  From 


-•  LONGITUDINAL 

Z  SECTION    OF 

5  THE    SMALL 

D  INTESTINE 

o 

i. 

c 


Fig.  26.  A  cross-section 
of  the  wall  of  the  small  in- 
testine magnified. 


FOOD  AND  HEALTH  135 

here  the  blood  goes  through  other  veins  to  the  right 
auricle  of  the  heart.  Then  it  is  sent  to  the  lungs  to  get 
a  supply  of  oxygen,  after  which  it  returns  to  the  heart 
to  be  distributed  throughout  the  body. 

Hygiene  of  eating.  If  the  food  that  you  eat  does 
for  you  all  that  it  should,  you  must  observe  certain 
rules  and  regulations.  First  of  all,  you  should  chew 
your  food  thoroughly. 

One  reason  for  thorough  chewing  is  that  it  gives  an 
opportunity  for  a  larger  amount  of  saliva  to  mix  with 
the  food  and  help  to  change  the  starch  to  sugar.  The 
other  reason  is  that  by  breaking  up  the  foods  the  gas- 
tric juice  in  the  stomach  has  a  better  opportunity  to  act 
upon  the  proteids. 

A  second  rule  to  observe  is  to  eat  regularly,  that 
is,  eat  at  meal  time  and  not  between  meals,  unless  you 
are  really  hungry.  If  you  have  an  early  breakfast 
and  become  very  hungry  before  the  noon  meal,  form 
the  habit  of  eating  a  small  amount  or  drinking  a 
glass  of  milk  about  the  middle  of  the  forenoon. 
Avoid  eating  candy,  nuts,  ice  cream,  etc.,  between 
meals.  Such  things  are  best  eaten  as  desserts  of  the 
noon  or  evening  meals. 

Third,  eat  plenty  of  vegetables  and  fruits  and  not 
much  meat.  Meat  once  a  day  is  enough  for  any 
healthy  person. 

Fourth,   avoid  stimulants  of  all  kinds.     Tea  and 


136  STUDIES  IN  SCIENCE 

coffee  are  not  good  for  children.  Alcoholic  drinks 
are  generally  injurious  to  health  and  rarely  do  any 
good  even  when  used  as  medicine.  Everyone  knows 
how  harmful  they  are.  Patent  medicines  should  also 
be  avoided.  They  are  the  source  of  much  trouble  in 
the  digestive  organs.  Medicine  should  be  taken  only 
under  the  advice  of  a  physician. 

The  teeth.  If  you  examine  your  mouth  in  the  mir- 
ror you  will  find  that  you  have  in  the.  back  part  of 
your  jaw  on  each  side,  two  or  three  broad,  flat  teeth. 
These  are  called  molars  and  their  sole  purpose  is  to 
crush  and  grind  up  the  solid  food  till  it  is  reduced  to  a 
pulp.  Most  people  do  not  get  the  last  molars,  known 
as  the  wisdom  teeth,  until  they  are  from  sixteen  to 
twenty  years  of  age.  In  front  of  the  molars  on  each 
side  are  somewhat  smaller  teeth  which  also  aid  in 
grinding.  These  are  called  bicuspids.  In  front  of 
the  bicuspids  are  the  sharp  tearing  teeth  called 
canines,  and  in  front  of  these  the  two  cutting  teeth 
called  incisors. 

Care  of  teeth.  To  keep  the  teeth  in  good  condition 
is  a  prime  requisite  to  good  health.  Teeth  that  are 
not  kept  clean  serve  as  a  lurking  place  for  all  sorts 
of  disease  bacteria.  If  particles  of  food  are  left  in  the 
mouth,  around  and  between  the  teeth,  they  form  an 
excellent  place  for  bacteria  to  grow  and  multiply. 
Physicians  believe  they  have  good  evidence  that  the 


FOOD  AND  HEALTH  137 

ill  health  of  many  people  may  be  traced  directly  to 
teeth  that  are  in  bad  condition. 

The  teeth  should  be  brushed  at  least  once  every 
day,  better  twice.  The  mouth  should  be  rinsed  thor- 
oughly with  water  after  each  meal.  A  dentist  should 
be  visited  at  least  once  a  year,  better  twice,  so  that 
he  may  detect  any  evidence  of  decay  in  the  teeth  and 
attend  to  the  matter  at  once.  Thousands  of  young 
people  through  lack  of  care  lose  second  teeth  that 
could  easily  be  saved  for  service  and  beauty  during 
many  years. 

Care  of  foods.  Foods  should  be  so  cared  for  that 
there  may  be  little  danger  of  spreading  disease 
through  them.  Foods  that  are  exposed  to  dust  in 
stores  or  on  the  street  should  be  thoroughly  washed 
before  eating,  especially  those  that  are  eaten  raw.  Ves- 
sels in  which  foods  are  kept  should  be  carefully 
washed  and  sterilized  with  boiling  water,  and  occa- 
sionally left  standing  out  in  the  hot  sun. 

People  who  cook  food  should  use  the  greatest  care 
to  cleanse  their  hands  and  nails  perfectly  before  they 
handle  the  food.  Under  no  consideration  should  one 
who  is  waiting  on  a  sick  person  go  into  the  kitchen 
to  cook  without  first  washing  his  hands  in  a  weak 
solution  of  cabolic  acid  or  other  disinfectant. 

Food  should  be  kept  from  spoiling  by  keeping  out 
bacteria  as  much  as  possible;  that  is,  by  cleanliness, 


138  STUDIES  IN  SCIENCE 

and  by  keeping  the  foods  cool  so  that  bacteria  will 
not  grow  and  multiply  in  them. 

All  the  people  in  a  community  who  are  thoughtful 
about  health  conditions  should  cooperate  to  see  that 
stores  and  markets  in  which  food  is  sold  are  kept 
absolutely  clean  and  sanitary. 


SPRING  STUDIES 

CHAPTER  X 

GARDEN  STUDIES  AND  HOME  PROJECTS 

Getting  ready  for  the  garden.  Gardening  should 
mean  something  more  to  you  than  merely  planting, 
cultivating  and  harvesting  crops.  Through  it  you 
will  be  able  to  discover  many  scientific  truths  and 
underlying  principles  concerning  the  life  and  habits 
of  plants,  kinds  of  soil,  principles  of  drainage  and 
the  vitality  of  seeds.  This  means  that  special  studies 
and  experiments  must  go  along  with  your  garden- 
ing. Then,  too,  you  must  conduct  your  work  accord- 
ing to  sound  business  principles  if  you  wish  to  get 
real  value  out  of  it. 

One  of  the  first  things  to  do  is  to  write  to  seed 
firms  for  catalogues  and  send  for  your  seeds.  There 
are  a  number  of  associations  and  seed  houses  that 
make  special  prices  to  school  children.* 

Look  over  the  garden  projects  suggested  in  this 
chapter  before  you  decide  definitely  what  to  plant. 

*Two  of  these  are:  The  Children's  Flower  Mission,  Cleveland, 
Ohio;  The  School  Garden  Association,  Boston,  Mass. 

139 


140  STUDIES  IN  SCIENCE 

You  should  be  influenced  in  your  decision  by  the 
disposal  you  expect  to  make  of  your  garden  products. 
If  you  are  planning  to  use  your  vegetables  upon  the 
home  table,  you  should  consult  with  the  family  to 
find  out  what  they  prefer.  If  you  expect  to  market 
your  produce,  you  should  find  out  from  grocerymen 
or  truck  gardeners  what  vegetables  are  likely  to  be 
in  greatest  demand. 

It  is  worth  while  also,  if  you  have  a  good  sized 
plot,  to  give  a  small  space  to  new  or  unusual  vege- 
tables. There  are  a  number  of  palatable  and  nutri- 
trious  vegetables  that  many  people  do  not  grow  or 
use  because  they  know  nothing  about  them.  You 
may  succeed  in  introducing  some  of  these  into  your 
home  and  neighborhood.  If  you  have  a  small  plot  on 
the  school  grounds  it  may  be  used  as  an  experimental 
garden  in  which  new  varieties  of  vegetables  may  be 
grown  and  tested.  The  small  school  plot  may  also 
be  used  to  demonstrate  some  of  the  principles  of 
gardening,  as  well  as  to  raise  material  for  special 
study. 

Tools.  If  you  are  starting  a  garden  for  the  first 
time,  you  will  have  to  purchase  tools  with  which  to 
work,  unless  your  parents  have  all  that  are  neces- 
sary. If  they  garden  on  a  large  scale,  they  prob- 
ably use  some  implements  such  as  plows,  harrows 
and  cultivators  drawn  by  horses.  If  you  have  a  small 


GARDEN  STUDIES  AND  HOME  PROJECTS  141 

garden  of  your  own,  you  will  need  the  following  hand 
tools: 

1.  For  preparing  the  seed-bed:     a  spade,  spading 
fork,  rake. 

2.  For  planting:  a  line,  or  measuring  stick,  hoe. 

3.  For  cultivating:  hoe,  hand  weeder,  wheel  hoe. 

4.  For  raising  plants  indoors :  shallow  boxes,  called 
flats. 

5.  For  transplanting:   a  trowel,  dibber,  watering 
can. 

Making  a  hotbed.  A  hotbed  is  an  inexpensive  and 
convenient  place  in  which  to  raise  plants  that  must 
be  started  very  early  in  the  season  and  transplanted 
afterwards. 

The  parts  of  a  hotbed  are:  1.  The  pit  in  which 
material  is  placed  to  furnish  artificial  heat.  2,  The 
frame.  3.  The  sash. 

The  pit  should  be  of  such  size  that  the  sash  will 
just  cover  it;  an  ordinary  hotbed  sash  is  six  feet  long 
and  three  feet  wide.  A  small  hotbed  then,  may  be 
made  3x6  ft.,  6x6  ft.,  3x12  ft.,  according  to  the  num- 
ber of  sashes.  If  you  have  an  old  window  sash  about 
•the  place,  the  pit  may  be  made  to  fit  this  sash. 

Dig  the  pit  about  two  feet  deep  in  a  well  drained 
spot.  Place  posts  in  the  corners  and  nail  planks  to 
these.  This  makes  the  frame.  The  posts  should 
extend  twelve  inches  above  the  ground  on  the  north 


142 


STUDIES  IN  SCIENCE 


m$w 


CM 

feb 


GARDEN  STUDIES  AND  HOME  PROJECTS  143 

side  and  eight  inches  on  the  south,  thus  making  your 
bed  slope  toward  the  south. 

When  the  pit  with  the  frame  is  ready,  procure  some 
fermenting  stable  manure,  which  is  from  one-third  to 
one-half  straw  or  litter  used  for  bedding.  Several 
days  before  making  the  hotbed  the  manure  should 
be  placed  in  a  pile  four  or  five  feet  high  so  that  fer- 
mentation will  begin.  It  should  be  turned  over  with 
a  fork  so  that  it  will  ferment  evenly  in  all  parts. 
Place  a  layer  of  this  in  the  bottom  of  the  pit  and 
tramp  or  pound  it  down.  Continue  putting  in  layers 
and  tramping  them  until  the  manure  is  from  fourteen 
to  fifteen  inches  deep.  On  top  of  this  place  a  layer 
of  good  soil  about  four  inches  in  depth. 

If  the  bed  is  more  than  three  feet  long,  place  sup- 
ports for  the  sashes  every  three  feet.  If  it  is  very 
cold  weather,  a  double  sash  should  be  used.  A  layer 
of  manure  piled  around  the  frame  on  the  outside  will 
be  of  service  in  conserving  the  heat. 

Planting.  The  hotbed  is  now  ready  for  use  unless 
the  temperature  is  too  high.  Heat  is  produced  by 
chemical  changes  that  are  taking  place  in  the  decay- 
ing manure.  Place  a  thermometer  in  the  soil  and  wait 
for  the  right  temperature.  A  few  plants  like  egg 
plants,  peppers,  or  tomatoes  may  be  planted  when 
the  temperature  is  between  85°  and  90°  F.  For  most 
seeds  a  temperature  between  70°  and  80°  F.  is  safest. 


144  STUDIES  IN  SCIENCE 

Plant  your  seeds  in  rows,  extending  north  and  south. 
You  may  put  the  rows  quite  close  together,  from  four 
to  six  inches.  The  soil  should  be  slightly  moist  when 
you  plant  the  seeds.  Firm  the  soil  over  the  seeds 
just  as  you  would  if  you  were  planting  them  out-of- 
doors  in  the  garden. 

Care  of  the  hotbed.  Three  conditions  are  essential 
in  having  your  plants  grow  successfully  in  a  hotbed: 

1.  The  temperature  must  be  kept  as  even  as  pos- 
sible. 

2.  The  soil  must  be  kept  moist. 

3.  The  plants  must  receive  a  supply  of  fresh  air. 
Watering   should   be   done  in   the  morning   rather 

than  in  the  evening.  On  bright  warm  days  the  sash 
should  be  lifted  a  little,  from  one  to  three  inches,  in 
order  to  admit  fresh  air  and  allow  impure  air  to 
escape.  It  may  be  left  open  twTo  or  three  hours  in 
the  middle  of  the  day.  If  the  weather  turns  sud- 
denly cold,  an  extra  covering  of  boards,  pieces  of  old 
carpets  or  canvas  should  be  thrown  over  the  hotbed 
at  night. 

A  hotbed  in  connection  with  a  school  garden  may 
furnish  enough  plants  for  all  the  children  to  set  out 
in  their  home  or  individual  gardens. 

Hotbeds  are  sometimes  used  to  raise  certain  plants 
as  lettuce,  radishes  and  spinach  for  table  use  during 
cold  weather.  Sometimes  steam  or  hot  water  pipes 


GARDEN  STUDIES  AND  HOME  PROJECTS  145 

are  used  instead  of  manure  to  produce  the  needed 
heat. 

Cold  frames.  A  cold  frame  is  another  device  for 
raising  plants  that  are  to  be  transplanted.  It  is  sim- 
ilar to  the  hotbed  except  that  it  does  not  have  the 
manure  to  produce  artificial  heat.  It  consists,  then, 
of  the  frame  and  the  sash.  A  frame  may  be  made 
so  that  it  may  be  moved  from  one  place  to  another. 


Fig.  28.     A  cold  frame. 

The  frame  should  be  twelve  inches  high  on  one  side 
and  eight  inches  on  the  other,  just  as  the  frame  of 
the  hotbed.  It  should  also  be  the  proper  length  and 
width  to  fit  the  sashes.  It  may  be  placed  in  a  well 
drained  spot  in  the  garden.  The  soil  should  be  dug 
and  thoroughly  pulverized  before  the  frame  is  put 
into  place.  A  layer  of  manure  around  the  outside 
will  help  to  keep  the  temperature  even. 


146  STUDIES  IN  SCIENCE 

A  cold  frame  may  be  used  to  start  certain  plants 
that  later  may  be  transplanted  to  the  garden.  Cab- 
bage, cauliflower,  tomato  plants,  brussels  sprouts, 
and  kohl-rabi  may  be  grown  successfully  in  a  cold 
frame,  planting  them  the  latter  part  of  March  or  the 
first  of  April.  Some  flowering  plants  from  which 
you  wish  to  get  early  results  as  cosmos,  gaillardia, 
sweet  scabious  and  salvia,  may  be  started  in  the  cold 
frame  and  then  transplanted  to  the  garden. 

The  care  of  plants  in  the  cold  frame  is  similar  to 
that  employed  in  the  use  of  the  hotbed. 

Cold  frames  are  frequently  used  to  harden  plants 
that  have  been  grown  in  hotbeds  before  setting  them 
out  in  the  garden. 

Do  you  know  why  the  temperature  of  the  cold  frame 
is  warmer  than  the  outside  air!  The  answer  involves 
a  principle  of  physics.  The  heat  rays  of  the  sun 
pass  through  the  transparent  glass  and  heat  the  soil 
in  the  cold  frame.  The  heat  that  radiates  from  the 
soil  cannot  pass  out  through  the  glass,  so  you  see  it 
must  accumulate  inside  the  frame. 

Preparing  the  seed-bed.  To  insure  a  successful  gar- 
den you  must  see  that  the  soil  is  in  good  condition 
before  you  plant  your  seeds  or  set  out  your  plants. 

Plow  or  spade  it  to  a  depth  of  from  10  to  12  inches. 
A  spading  fork  will  give  better  results  than  a  spade. 
Then  pulverize  it  with  a  harrow  or  rake  till  it  is  fine 


GARDEN  STUDIES  AND  HOME  PROJECTS  147 

and  mellow.  If  it  is  a  clay  soil  be  careful  not  to  work 
it  when  it  is  very  wet.  If  when  you  take  up  a  hand- 
ful and  squeeze  it  the  particles  stick  together  and 
will  not  fall  apart  when  you  drop  the  lump,  it  is  too 
wet.  If  the  particles  fall  apart  the  soil  is  in  good 
condition  so  far  as  moisture  is  concerned. 

In  order  to  have  a  successful  garden  it  must  be 
well  drained,  must  be  rich  in  organic  matter  or  humus, 
and  contain  in  available  form  all  the  soil  elements 
that  plants  need  for  their  growth.  In  order  to  keep 
the  soil  in  excellent  condition,  with  a  constant  supply 
of  moisture,  you  must  cultivate  your  garden  fre- 
quently. Never  allow  a  crust  to  form  and  remain. 
This  means  cultivating  after  every  rain. 

BOYS  AND  GIRLS  CLUBS 

While  any  of  the  projects  suggested  in  this  and  other  chapters 
may  be  undertaken  individually  in  your  home,  it  will  add  both 
interest  and  profit  to  the  work  if  a  number  of  boys  and  girls  of 
the  community  meet  and  organize  a  club.  Here  various  kinds  of 
work  may  be  discussed  and  you  can  decide  what  particular  projects 
you  wish  to  undertake  as  a  club.  The  value  of  the  club  is  that  it 
affords  an  opportunity  to  learn  much  from  each  other  about  the 
work.  You  will  be  more  interested  in  the  work  itself  when  you 
know  what  others  are  accomplishing.  Then,  too,  it  affords  an  ex- 
cellent opportunity  to  receive  some  training  in  conducting  public 
meetings,  in  parliamentary  practice,  and  in  speaking  before  the 
public. 

Many  state  universities  have  in  cooperation  with  the  U.  S.  De- 
partment of  Agriculture  and  the  Bureau  of  Education  a  club  leader 
who  gives  his  entire  time  to  the  work  of  helping  boys  and  girls  to 
form  clubs  and  to  carry  on  projects  in  connection  with  them.  If 


148  STUDIES  IN  SCIENCE 

you  wish  to  organize  a  club  the  first  thing  you  should  do  is  to  apply 
to  the  club  leader  of  your  state  for  information.  He  will  send  you 
bulletins  and  other  material  explaining  exactly  how  to  proceed. 


PROJECT  ONE 

TOMATOES 

Material.     Seeds  and  seed  catalogues ;  flats  or  boxes. 

If  you  are  planning  to  raise  tomatoes,  you  should 
decide  first  of  all  whether  you  want  to  try  more  than 
one  variety.  Looking  in  your  seed  catalogue  you 
find  some  listed  as  early  varieties,  other  as  late. 
Usually  the  early  tomatoes  are  smaller  than  the  main 
crop  tomatoes.  It  is  worth  while  to  grow  a  few  of 
these  for  early  market  or  home  use;  for  canning  the 
larger  varieties  are  better. 

Planting.  If  you  live  in  a.  warm  climate  plant  your 
seeds  out-of-doors;  if  in  a  cool  climate,  you  must  start 
them  in-doors.  Can  you  explain  why?  It  is  because 
the  tomato  is  not  hardy  enough  to  plant  out-of-doors 
early  in  the  spring  in  a  cold  climate.  If  you  wait 
until  the  ground  is  warm  enough  for  the  seeds,  the 
season  will  be  too  short  for  the  fruit  to  ripen. 

Place  some  good  rich  soil  in  a  box.  Use  a  flat 
or  a  shallow  box  about  two  and  one-half  or  three 
inches  deep.  Scatter  the  seed  broadcast  over  the 
soil  or  sow  in  drills  two  inches  apart.  Cover  with 
about  one-half  inch  of  soil  and  firm  the  soil  well. 


GARDEN  STUDIES  AND  HOME  PROJECTS  149 

If  you  have  a  hotbed,  place  the  flat  in  this;  keep 
well  watered  and  ventilated.  If  you  have  no  hot- 
bed, the  plants  will  do  fairly  well  in  a  sunny  window 
in  the  school  room,  or  in  the  kitchen.  Care  should  be 
taken  not  to  allow  them  to  chill  on  cold  nights. 

If  the  plants  are  not  too  crowded,  they  may  be  left 
in  the  flats  until  time  to  transplant.  You  will  get 
better  results,  however,  if  when  the  plants  are  between 
two  and  three  inches  high  you  transplant  them  to 
small  flower  pots,  old  berry  boxes,  tin  cans  or  into 
other  flats.  If  you  use  the  cans,  be  sure  to  punch 
holes  in  the  bottom  for  drainage.  Do  not  keep  the 
plants  too  warm,  but  allow  them  to  grow  rather 
slowly  in  order  to  form  a  thick  stocky  stem. 

Transplanting.  When  all  danger  of  frost  is  past, 
transplant  to  the  garden.  The  small  early  varieties 
may  be  placed  two  and  one-half  or  three  feet  apart; 
the  large  ones  from  three  to  four  feet. 

Care  of  plants.  As  you  know,  the  tomato  plant  has 
a  weak  stem  which  if  left  to  itself  will  spread  over 
the  ground.  To  get  best  results  you  should  make  a 
support  of  some  sort.  Soft  twine  or  strips  of  cloth 
should  be  used  to  tie  the  plants  to  the  support. 

It  is  not  well  to  allow  all  the  buds  that  appear  to 
develop.  If  you  look  closely  at  your  plants  when 
they  are  four  or  five  inches  high  you  find  new  buds 
appearing  in  the  axils  of  the  leaves.  Most  of  these 


150  STUDIES  IN  SCIENCE 

should  be  pinched  out.  This  compels  the  plant  to 
grow  tall.  When  your  plant  has  a  number  of  fruit 
clusters  on  it,  you  may  prevent  its  growing  taller 
by  pinching  out  the  top  bud.  You  should  cultivate 
frequently  enough  to  keep  a  soil  mulch. 

Experiments,  (a)  Test  two  or  three  varieties  to 
determine  which  gives  best  results,  (b)  Train  sev- 
eral plants  on  supports.  Leave  the  same  number 
untrained.  Keep  a  record  of  results. 

Harvesting  and  canning.  If  you  are  marketing 
your  crop,  be  careful  not  to  bruise  the  fruit.  Put 
together  the  tomatoes  that  are  similar  in  size,  shape 
and  color.  You  will  get  a  better  price  for  choice  fruit 
if  you  grade  it  carefully. 

Seventh  and  eighth  grade  girls  can  successfully 
can  tomatoes.  Select  firm,  thoroughly  ripe  fruit. 
The  skins  are  removed  by  placing  the  tomatoes  for 
a  few  seconds  in  water  heated  to  the  boiling  point. 
Eemove,  dip  immediately  into  cold  water,  and  the 
skins  will  slip  off  easily. 

There  are  two  methods  of  canning  that  you  may 
use.  The  old-fashioned  plan  is  to  cook  the  tomatoes, 
then  place  them  in  cans  and  seal.  First  the  cans,  tops 
and  rubbers  should  be  sterilized  by  immersing  in 
boiling  water. 

The  newer  and  better  plan  is  the  cold  pack  or  hot 
water-bath  method,  using  the  closed  boiler  or  the 


GARDEN  STUDIES  AND  HOME  PROJECTS  151 

home  canning  outfits.  Both  of  these  methods  with 
much  useful  information  are  described  and  explained 
in  Farmers'  Bulletin  No.  521,  "Canning  Tomatoes  at 
Home  and  in  Club  Work."  This  may  be  obtained 
free  by  sending  to  the  IT.  S.  Department  of  Agricul- 
ture, Washington,  D.  C. 

It  will  be  quite  worth  while  for  a  school  to  have 
in  connection  with  the  Domestic  Science  department 
a  canning  demonstration  with  a  wash  boiler  or  deep 
kettle  and  a  canning  outfit. 

You  may  use  your  tomatoes  also  for  pickles,  chow- 
chow,  piccalilli  and  sweet  preserves.  You  will  find 
recipes  for  these  in  the  bulletin  named  above. 

Record  of  Tomato  Project. 

1.  Name  of  variety. 

a.  Date  of  planting. 

b.  Date  of  transplanting. 

c.  Date  when  ready  for  use. 

2.  Expenditures. 

a.  Cost  of  seeds. 

b.  Rental  value  of  plot — size  of  plot. 

c.  Labor — Estimate  hours  of  work. 

d.  Cost  of  fertilizer. 

e.  Total  expenditure. 

3.  Receipts. 

a.  Yield  in  pounds  or  bushels. 

b.  Amount  sold — value. 

c.  Amount  used  or  canned — value. 

d.  Total  receipts. 

e.  Net  profits. 

4.  Note  any  points  that  will  be  of  value  for  future  reference. 


152  STUDIES  IN  SCIENCE 

PROJECT  TWO 

EOOT  CROPS 

Material.  Roots  of  beets,  turnips,  parsnip,  carrot, 
and  salsify;  seeds  of  each. 

Root  crops  is  a  name  given  by  market  gardeners  to 
plants  whose  roots  are  used  for  food.  Make  a  list  of 
all  the  root  crops  that  you  know.  Choose  any  one 
of  them  for  observation  and  study.  The  study  may 
be  made  late  in  the  fall  or  any  time  during  the  winter 
or  early  spring. 

Seed-bed  and  seeds.  Work  the  soil  thoroughly  so 
that  it  will  be  loose  and  deep.  It  should  also  be  well 
drained. 

The  seeds  of  most  root  crops  do  not  retain  their 
vitality  more  than  two  years.  It  is  safer  to  use  one- 
year-old  seeds. 

If  you  are  not  sure  that  the  seeds  are  fresh,  test 
them  to  see  if  they  will  germinate.  Place  a  few  in 
moist  sand  or  soil.  Keep  moist  but  not  too  warm 
and  watch  to  see  whether  they  will  germinate  and 
grow.  The  seeds  are  slow  to  germinate,  taking  from 
ten  days  to  three  weeks,  so  do  not  be  discouraged 
when  the  plants  do  not  appear  within  a  few  days. 
You  should  make  the  test  during  the  latter  part  of 
winter  or  early  spring. 

Planting.  Time:  All  the  root  crops  are  cool  weather 


GARDEN  STUDIES  AND  HOME  PROJECTS  153 

plants  and  may  be  planted  as  early  as  the  ground 
can  be  worked  in  the  spring.  Beets,  carrots,  and 
turnips  may  be  planted  at  intervals  during  the  sum- 
mer for  a  succession  of  crops. 

Distance  apart  of  rows:  Beets,  carrots,  parsnips, 
salsify,  turnips,  12  inches. 

Depth :  All  the  above  except  turnips,  1  inch.  Tur- 
nips l/2  inch. 

It  is  very  essential  to  firm  the  soil  well.  If  the 
seeds  germinate  they  must  be  kept  moist.  Firming 
the  soil  brings  it  in  close  contact  with  the  seeds,  so 
that  the  moisture  is  kept  constant  by  capillary  action 
of  the  soil. 

Some  gardeners  plant  small,  quick  germinating 
seeds,  as  radishes  or  lettuce,  in  the  rows  with  parsnips 
and  carrots.  These  help  to  break  the  crust  for  the 
slower  plants  and  at  the  same  time  mark  the  rows  so 
that  the  soil  can  be  cultivated  without  the  possibility 
of  injuring  the  young  seedlings  that  may  be  just  ready 
to  break  through. 

Thinning1.  It  is  a  good  plan,  in  order  to  secure  a 
good  stand,  to  plant  the  seeds  rather  close,  about  an 
inch  apart.  If  all  grow,  thin  to  a  distance  of  from 
3  to  4  inches. 

Harvesting.  Beets  will  be  ready  to  use  in  from 
8  to  10  weeks  after  planting.  They  are  much  better 
when  young  than  if  allowed  to  reach  their  full  growth. 


154  STUDIES  IN  SCIENCE 

They  may  be  canned  successfully  by  the  closed  boiler 
or  steam  method. 

Carrots  are  ready  for  use  in  from  12  to  15  weeks. 
They  too  are  better  young.  They  may  also  be  canned. 
Both  beets  and  carrots  bring  a  better  price  at  this 
time  than  later.  Turnips  are  ready  in  from  8  to  12 
weeks.  Parsnips  and  salsify  may  be  left  in  the 
ground  and  used  during  the  winter.  While  some 
people  think  that  frost  improves  them,  they  are  all 
right  to  use  in  the  early  fall. 

Any  of  the  root  crops  may  be  kept  fresh  and  crisp 
for  use  all  winter  by  placing  them  in  boxes  of  moist 
soil,  sand  or  leaves,  and  keeping  them  in  a  cold  cellar. 
A  temperature  just  above  freezing  is  best.  They  may 
also  be  kept  in  pits  out-of-doors.  To  preserve  them 
in  this  way  they  should  be  placed  in  a  conical  pile, 
covered  with  six  or  eight  inches  of  straw,  then  with 
a  layer  of  earth.  In  very  cold  regions  a  layer  of 
manure  may  be  put  on  top  of  the  soil. 

Experiment,  (a)  If  you  have  an  experimental  plot, 
set  out  some  roots  of  beets,  carrots,  etc.,  and  raise 
some  seeds  of  your  own. 

(b)  Try  different  varieties  of  any  of  the  root  crops 
suggested  to  determine  which  give  best  results  in  your 
garden. 

Keep  a  record  of  your  crop  similar  to  the  one  sug- 
gested for  tomatoes. 


GARDEN  STUDIES  AND  HOME  PROJECTS  155 

PROJECT  THREE 

POTATOES 

Material.  A  number  of  potatoes,  a  small  bottle  of 
tincture  of  iodine,  some  red  ink. 

Study.  Examine  a  potato.  What  do  you  find  scat- 
tered over  the  surface?  Where  are  the  eyes  most 
numerous  ?  Where  are  the  smallest  ones ;  the  largest ? 
What  are  the  eyes?  Do  any  of  them  show  signs  of 
growth!  What  else  do  you  find  on  the  potato! 

The  eyes  are  buds,  and  the  end  of  the  potato  on 
which  the  eyes  are  so  numerous  is  called  the  bud  or 
seed  end.  Opposite  this  is  the  stem  end. 

What  is  the  potato?  To  answer  this,  hold  a  potato 
with  the  bud  end  upward.  Now  suppose  you  could 
stretch  it  out  many  times  its  length  and  have  the 
thickness  reduced  accordingly.  What  part  of  a  plant 
would  it  resemble!  • 

Cut  a  potato  in  two  through  one  of  the  eyes.  How 
many  different  structures  has  it! 

Experiment.     What  is  the  potato  made  of? 

1.  Weigh  a  potato  after  first  removing  the  peel- 
ing.   Put  it  in  a  warm  place.    What  happens?    After 
a  few  days  weight  it  again.    How  much  has  it  lost? 
What  causes  the  loss? 

2.  Scrape   the   white   portion   from   two    or   three 
potatoes.     Put  the  scrapings  into  a  glass  of  water. 


156  STUDIES  IN  SCIENCE 

Stir  thoroughly.  Allow  the  glass  to  stand  for  twen- 
ty-four hours.  What  do  you  find  in  the  bottom? 
Carefully  pour  off  the  scraps  and  water  leaving  noth- 
ing but  the  white  layer  in  the  bottom.  Pour  a  small 
amount  of  boiling  water  over  this.  What  happens! 
Put  a  few  drops  of  iodine  on  the  starch  and  note 
effect. 

Experiment.  Of  what  use  is  the  starch  to  the 
potato?  Fill  a  box  or  large  flower  pot  nearly  full 
of  soil.  Plant  two  small  sized  potatoes.  Cover  about 
two  and  a  half  inches  deep.  Keep  watered.  When 
the  plants  are  about  three  inches  high  dig  up  one  and 
examine  the  potato  noting  any  changes  that  have 
taken  place.  Leave  the  other  for  a  number  of  weeks, 
then  examine  it.  The  same  experiment  may  be  tried 
to  better  advantage  out-of-doors  in  the  garden. 

Experiment.  Cut  a  slice  from  the  stem  end  of  a 
potato  tuber.  Set  the  cut  end  of  the  tuber  in  a  dish 
with  about  a  quarter  of  an  inch  of  red  ink  in  the  bot- 
tom. Allow  it  to  stand  several  hours.  Now  make 
a  number  of  thin  slices.  What  has  taken  place? 

Discussion.  The  fact  that  the  potato  has  buds  tells 
you  that  it  is  a  stem.  Since  it  grows  in  the  ground 
it  is  an  underground  stem.  There  are  several  differ- 
ent kinds  of  underground  stems.  This  kind  is  called 
a  tuber.  In  propagating  potatoes  then  we  use  tubers 
instead  of  seeds. 


GARDEN  STUDIES  AND  HOME  PROJECTS  157 

The  tuber  is  made  up  chiefly  of  water  and  starch. 
The  blue  color  that  appeared  when  you  used  the 
iodine  indicated  the  presence  of  starch.  The  potato 
also  contains  a  few  minerals.  Its  structure  is  like 
that  of  any  stem.  The  outside  layer  we  call  the  peel- 
ing. The  dark  line  is  the  woody  tissue.  The  part 
between  the  wood  and  peeling  is  the  cortex.  The 
dark  central  part,  with  the  rays  extending  from  it, 
is  the  pith.  The  white  part  is  called  the  medulla. 
Your  experiment  shows  that  the  woody  tissue  carries 
water  and  other  food  materials  to  the  tuber. 

Pla.nting.  Time:  Early  potatoes  may  be  planted 
as  soon  as  the  ground  is  dry  enough  to  cultivate  in 
the  spring.  Late  varieties  may  be  planted  in  May 
or  June.  The  northern  states  that  raise  quantities 
of  potatoes  usually  plant  them  about  the  middle  of 
May. 

The  seed-bed:  Potatoes  need  a  deep,  rich,  mellow 
seed-bed.  To  insure  this  the  soil  should  be  plowed 
deeply  and  then  disked  or  harrowed  a  number  of 
times.  A  soil  that  has  had  clover  or  alfalfa  growing 
on  it  the  year  before  is  excellent  for  potatoes. 

Cutting  the  tubers:  Many  experiments  have  been 
made  at  agricultural  stations  to  determine  the  most 
economical  way  to  cut  the  tubers  for  planting.  A 
chunky,  compact  piece  with  at  least  two  eyes  usually 
gives  best  results. 


158  STUDIES  IN  SCIENCE 

Space  between  rows:  In  Jhe  garden,  wliere  hand 
cultivation  is  practiced  the  rows  may  "be  2%  feet 
apart.  When  the  horse  cultivator  is  to  be  used  they 
should  be  3  feet  apart. 

Space  between  hills:  12  to  15  inches.  Plant  one 
piece  in  each  hill. 

Depth:  In  heavy,  compact  soil  3  inches.  In  loose, 
mellow  soil  4  to  5  inches. 

Cultivation  and  care.  Work  the  soil  frequently; 
harrow  the  ground  at  least  once  before  the  plants 
are  up.  All  through  the  growing  season  cultivate 
often  enough  to  keep  the  soil  fine  and  loose.  Care 
should  be  taken  not  to  cultivate  too  deeply  lest  the 
roots  be  injured. 

Enemies.  If  you  find  traces  of  the  fungous  disease 
called  scab  on  your  seed  potatoes  you  can  prevent  its 
attacking  your  new  potatoes  by  treating  the  seed 
with  a  solution  of  formaldehyde.  Use  one  ounce  to 
two  gallons  of  water.  Leave  the  potatoes  in  the  solu- 
tion from  one  and  a  half  to  two  hours. 

The  Colorado  potato  beetle  is  likely  to  be  your 
worst  foe.  For  treatment,  spray  with  arsenate  of 
lead  or  Paris  green. 

For  potato  blight  spray  with  Bordeaux  mixture 
or  lime-sulphur  mixture.  The  latter  will  also  kill 
aphids  or  plant  lice. 

Harvesting,   marketing  and  storing.    Early,  potar 


GARDEN  STUDIES  AND  HOME  PROJECTS  159 

toes  may  be  dug  for  market  when  they  are  large 
enough  to  use  before  they  are  fully  matured.  If  you 
are  planning  to  sell  your  crop  you  may  get  a  better 
price  for  it  at  this  time  than  if  you  wait  until  later. 

You  will  probably  harvest  your  main  crop  when 
the  potatoes  are  mature.  This  means  when  the  vines 
are  dead.  If  you  store  them  for  future  use  or  plan 
to  sell  them  later  you  should  keep  them  in  a  cool, 
dark  place  at  a  temperature  from  33°  to  35°  F.  They 
may  be  stored  in  a  cool  cellar  or  in  an  outdoor  pit. 

Selecting  seed  potatoes.  When  digging  your  pota- 
toes watch  for  hills  that  give  the  best  yield;  that  is, 
the  greatest  number  of  large,  well  formed  potatoes. 
Save  these  for  seed  next  year.  If  you  do  not  get 
enough  choice  ones  to  plant  your  entire  plot,  use 
these  to  plant  a  small  plot  and  from  this  again  choose 
the  best  hills.  In  the  course  of  three  or  four  years, 
by  this  simple  plan  of  selection  you  may  produce  a 
seed  potato  that  will  be  worth  many  times  the  price 
of  ordinary  potatoes. 

Keep  a  record  of  your  project  similar  to  that  sug- 
gested for  tomatoes. 

Experiments.  There  are  a  number  of  interesting 
experiments  that  you  may  make  either  at  home  or 
in  the  school  garden. 

1.  Does  careful  selection  of  seed  potatoes  pay? 
Plant  two  plots  of  equal  size,  one  with  tubers  care- 


160  STUDIES  IN  SCIENCE 

fully  selected  as  suggested  above,  the  other  with  tub- 
ers taken  at  haphazard  from  the  bin.  Give  both  the 
same  cultivation.  Compare  weights  when  the  crops 
are  harvested. 

2.  Is  it  worth  while  to  treat  potatoes  for  scab! 
Plant  two  plots  of  equal  size  with  the  same  kind  of 
potatoes.     Treat    the   tubers    of   one   with   formalin; 
plant  the   other  writh  untreated  potatoes.     Compare 
as  to  yield  and  quality  of  potatoes. 

3.  What    is    the    effect    of    frequent    cultivation? 
Plant  two  plots  of  equal  size  with  the  same  kind  of 
potatoes.     Cultivate   one  twice  as  frequently  as  the 
other.     Compare  yields.     Keep  a  record  of  the  extra 
time  and  labor  expended  so  you  may  take  that  into 
consideration  when  you  check  up  results. 

4.  Test  two  or  three  varieties  of  potatoes  as   to 
yield  and  quality.    Plant  plots  of  equal  size  and  give 
similar  culture.    Some  of  the  common  early  varieties 
are  Early  Chios,  Early  Eose,  Irish  Cobbler  and  Early 
Puritan.     The  leading  late  varieties  are  Rural  New 
Yorker,  Seneca  Beauty,  Burbank  and  Green  Mountain. 

PROJECT  FOUR 

ONIONS 

Material.     Some  large   onions,   several  onion   sets, 

seeds,  and  if  possible  a  stem  with  top  sets  or  bulblets. 

Study.    An  onion  is   a  bulb.     Examine  one  care- 


GARDEN  STUDIES  AND  HOME  PROJECTS  161 

fully.  What  do  you  find  at  the  lower  end?  At 
the  upper  end?  Describe  the  covering.  Cut  one  bulb 
crosswise  and  another  lengthwise.  Of  what  is  the 
bulb  composed?  Where  are  the  thickest  layers? 
What  is  the  color  of  the  central  portions?  Look 
closely  at  the  place  where  the  layers  are  fastened. 
What  is  their  relation  to  the  hard  flat  plate  that  you 
found  on  the  outside  of  the  bulb?  How  is  the  cen- 
tral shoot  related  to  this?  What  is  this  plate? 

Experiment.  Wliat  is  the  value  to  the  onion  of 
the  thick,  juicy  layers? 

Place  a  medium  sized  onion  in  the  mouth  of  a  large 
bottle  full  of  water.  The  lower  part  of  the  bulb 
should  rest  in  the  water.  Watch  its  growth  for  a 
number  of  weeks.  Describe  the  roots  and  the  leaves. 
Explain  the  change  that  takes  place  in  the  bulb. 

Compare  sets  with  large  onions,  noting  differences 
and  resemblances.  How  are  the  sets  obtained?  If 
you  have  some  top  onions  or  bulblets,  compare  those 
with  the  sets. 

Examine  the  seeds.  Note  size,  color  and  shape. 
How  can  you  obtain  onion  flowers  and  seeds? 

Discussion.  The  onion  bulb  is  really  composed  of 
thick,  juicy,  modified  leaves  that  contain  a  large 
amount  of  food.  The  flat  plate-like  portion  to  which 
they  are  fastened  is  the  true  stem  of  the  bulb.  You 
find  from  your  experiment  that  the  bulb  sends  out 


162  STUDIES  IN  SCIENCE 

the  fibrous  roots  below  and  the  green  shoot  above. 
If  you  examine  the  latter  after  a  number  of  weeks, 
you  find  that  most  of  the  food  in  it  has  been  used  up 
and  it  has  become  very  soft  and  flabby. 

Sets  and  seeds.  Sets  are  small  bulbs  that  have 
been  grown  from  seeds  the  year  before.  In  some 
places  the  seeds  are  planted  late  in  the  season  and  in 
the  fall  the  small  bulbs  are  taken  up  and  stored  over 
winter.  Most  growers  of  sets,  however,  plant  the 
seeds  very  thick  early  in  the  spring.  The  plants  are 
so  crowded  that  the  bulbs  cannot  grow  large.  When 
the  tops  begin  to  die  the  small  bulbs  are  taken  up, 
dried  and  stored.  Top  sets  or  bulblets  are  produced 
by  certain  kinds  of  onions.  They  may  be  used  to 
produce  new  onions  just  as  the  true  sets  are  used. 

Onions  are  biennials,  so  if  you  wish  to  raise  seeds 
you  must  set  out  the  large  bulbs  which  send  up  a 
flowering  stem.  Sometimes  the  large  sets  will  do 
the  same  thing.  If  they  send  up  seed  stalks  they 
become  tough  and  strong  and  are  worthless.  Sets 
from  %  to  %  of  an  inch  in  diameter  are  the  best 
size  to  use  if  you  wish  to  raise  ripe  onions.  The 
larger  sets  may  be  used  for  green  or  bunch  onions. 

Planting.  There  are  several  different  methods 
which  you  may  use  to  raise  an  onion  crop.  If  you 
wish  an  early  crop,  use  sets.  You  may  also  use  bulb- 
lets  or  you  may  procure  the  potato  onion  or  multi- 


GARDEN  STUDIES  AND  HOME  PROJECTS  163 

plier.  This  produces  numerous  bulbs  growing  around 
the  bulb  you  set  out.  For  an  early  crop  you  may  set 
out  multiplier  onions  in  the  fall.  In  a  cold  climate 
cover  them  lightly  with  leaves  or  straw.  They  will 
be  ready  for  use  very  early  in  the  spring.  For  the 
general  crop  plant  seeds.  Onions  are  hardy,  cool 
weather  plants,  and  it  is  quite  essential  to  plant  them 
very  early  so  they  may  get  a  good  start  before  hot 
weather. 

Distance  between  rows,  12  to  16  inches. 

Distance  between  sets  in  the  row,  3  inches. 

Sow  seeds  thick  and  later  thin  to  same  distances 
as  sets. 

Depth  of  seeds,  %  to  1  inch. 

Depth  of  sets,  place  so  the  shoot  will  just  come 
above  the  surface  of  the  soil. 

Firm  the  soil  well  over  both  sets  and  seeds. 

Care  of  plants.  Keep  well  weeded  and  cultivated. 
The  hand  and  the  hand  weeder  are  the  best  tools  to 
use  at  first  with  the  seedling  onions.  After  they  are 
three  or  four  inches  high  the  wheel  hoe  or  cultivator 
may  be  used. 

Harvesting,  marketing  and  storing.  Onions  raised 
from  sets  will  be  ready  for  use  in  from  four  to  six 
weeks.  Seed  onions  will  be  ready  in  from  ten  to 
twenty-five  weeks. 

If  you  live  near  a  market  where  green  or  "  bunch 


164  STUDIES  IN  SCIENCE 

onions"  are  in  demand,  it  may  pay  you  to  market 
some  of  your  onions  just  as  soon  as  they  are  large 
enough  to  eat.  Clean  them  carefully,  trim  off  the 
fibrous  roots  and  tie  them  in  bunches  of  ten  or  twelve. 

If  you  wish  to  wait  until  the  onions  are  ripe,  keep 
watch  of  the  tops.  As  soon  as  they  have  fallen  over 
and  turned  yellow  you  may  be  sure  that  your  onions 
are  in  good  condition  to  harvest.  Pull  them  and  twist 
off  the  tops.  Some  gardeners  leave  them  lying  in 
the  rows  in  the  garden  to  cure,  but  the  method  now 
employed  by  the  best  market  gardeners  is  to  place 
them  in  a  dry,  well  ventilated  place  in  the  shade 
rather  than  in  the  sun.  A  shed  or  corn  crib  will  serve 
the  purpose.  Spread  them  out  so  that  the  air  may 
circulate  well  among  them.  Do  not  allow  them  to 
freeze.  When  cold  weather  approaches  either  sell 
them  or  put  them  in  a  place  where  the  temperature 
remains  above  the  freezing  point. 

Keep  a  record  of  your  project  similar  to  the  one 
suggested  for  tomatoes. 

Onions  require  considerable  care  and  labor,  but 
if  you  succeed  in  raising  a  good  crop  you  will  find 
them  very  profitable. 

Experiments,  a.  Plant  equal  areas  with  sets  and 
seeds.  Keep  separate  records  to  determine  which  is 
more  profitable. 

b.    Plant  equal  areas  of  different  varieties  of  onions, 


GARDEN  STUDIES  AND  HOME  PROJECTS  165 

red,  white,  or  yellow.    Keep  careful  records  to  deter- 
mine which  gives  best  results. 

PROJECT  FIVE 

CUCUMBERS  AND  OTHER  CUCURBITS 

Material.  Seeds  of  squash,  pumpkin,  and  cucum- 
bers; small  flats  or  boxes,  soil  or  sand;  seed  cata- 
logues. 

If  you  are  planning  to  raise  cucumbers  or  any  of 
their  relatives,  consult  your  seed  catalog  to  decide 
what  varieties  you  wish  to  grow.  Some  cucumbers 
are  better  adapted  for  slicing  than  others,  while  some 
are  especially  good  for  pickling.  Some  varieties  of 
squashes  and  pumpkins  are  ready  for  use  in  the  sum- 
mer; other  are  not  ripe  until  fall. 

Seeds  and  seedlings.  Soak  some  seeds  twenty-four 
hours;  squash  or  pumpkin  seeds  are  best  for  this 
study  because  of  their  large  size.  Examine  a  seed 
and  determine  the  point  where  it  was  attached  to 
the  inside  of  the  fruit.  Remove  the  covering  and 
describe  what  you  find  on  the  inside.  Consult  Fig.  28 
to  get  the  names. 

Experiment.  What  part  of  the  plant  will  each  part 
of  the  seed  produce?  To  answer  this  question  plant 
three  or  four  seeds  each  of  squash,  pumpkin  and 
cucumber  in  a  box  of  sand  or  other  light  soil.  Keep 
in  a  warm  temperature  and  water  frequently  enough 


166  STUDIES  IN  SCIENCE 

to  keep  the  soil  moist.  Record  the  date  of  planting. 
When  the  plants  are  up  solve  the  following  problems: 

How  long  does  it  take  each  to  appear  above  the 
ground?  What  part  of  the  plant  appears  first?  Do 
the  seed  coats  come  up?  What  changes  take  place 
in  the  cotyledons?  Dig  up  one  of  the  plants  to  deter- 
mine what  part  of  the  seed  produces  the  root.  How 
do  the  first  pair  of  leaves,  the  cotyledons,  differ  from 
the  other  leaves  of  the  plant?  (You  may  have  to 
wait  some  weeks  to  answer  this  question.)  What 
finally  becomes  of  the  cotyledons?  Compare  the  seed- 
lings with  each  other  for  likenesses  and  differences. 

Discussion.  No  doubt  you  can  see  a  strong  family 
resemblance  among  the  seeds  and  seedlings.  The 
entire  family  are  natives  of  warm  regions. 

The  cotyledons  which  produce  the  first  leaves  have 
some  food  stored  in  them  which  starts  the  growth 
of  the  seedling.  Then  they  begin  the  work  of  manu- 
facturing food  for  the  plant  and  continue  to  do  this 
till  other  leaves  are  produced,  when  they  wither  and 
drop  off. 

Planting.  Time:  Cucumbers  and  their  kin  are 
warm  weather  plants  so  must  not  be  planted  until  all 
danger  of  frost  is  past  and  the  soil  is  warm.  The 
soil  should  be  well  pulverized  and  very  rich.  It  is 
sometimes  a  good  plan  to  spade  a  fertilizer  into  it 
two  or  three  weeks  before  planting  time. 


GARDEN  STUDIES  AND  HOME  PROJECTS  167 

There  are  two  methods  of  planting :  1.  The  mound 
hill,  which  is  raised  six  to  nine  inches  above  the  level 
of  the  garden.  2.  The  hill  on  a  level  with  the  garden 
soil.  Whichever  plan  you  use  put  ten  to  twelve  seeds 
into  each  hill.  This  provides  for  the  destruction  of 
some  of  the  plants  by  insects  and  yet  probably  leaves 
enough  to  insure  a  crop. 

Distance  apart  of  hills :  Depth : 

Cucumbers,  4  to  5  feet  1  to  1%  inches 

Muskmelons,  5  to  6  feet  1  to  ll/2  inches 

Watermelons,   8  to   12  feet  l1^  inches 

Squashes  and  pumpkins,  8  to  12  feet                                       2  inches 

Cucumbers  may  be  started  indoors  six  or  eight 
weeks  before  they  could  be  planted  outside.  Plant 
three  or  four  seeds  in  good  soil  in  an  old  berry  box. 
Or  cut  a  piece  of  grass  sod  about  three  inches  thick 
and  from  four  to  five  inches  square,  turn  it  upside 
down  and  plant  the  seeds  in  the  fine  soil.  Keep  in 
a  hotbed  or  green  house  until  danger  of  frost  is  past. 

Care  of  plants.  If  all  the  seeds  in  the  outdoor 
plantings  germinate,  allow  the  seedlings  to  grow  for 
a  while;  then  if  none  are  destroyed  by  insects,  pull 
the  weakest  plants  leaving  three  or  four  of  the  strong- 
est ones.  Cultivate  frequently  till  the  plants  have 
developed  thrifty  vines.  To  know  how  to  treat  insect 
and  fungous  enemies  of  your  cucurbits  see  page  222. 

Harvesting.     If  you  are  to  use  your  cucumbers  on 


168  STUDIES  IN  SCIENCE 

the  home  table,  gather  them  when  the  right  size  to 
slice  and  keep  in  a  cool  place.  Placing  them  in  a 
refrigerator  a  couple  of  hours  before  peeling  will 
improve  their  crispness.  It  is  a  mistake  to  allow 
them  to  stand  several  hours  in  salt  water.  This 
results  in  toughness.  Cucumbers  to  slice  are  usually 
in  demand  on  the  market.  Gather  them  every  day 
or  two,  and  use  the  same  care  to  keep  them  fresh  as 
you  w-ould  for  your  own  table. 

If  you  are  raising  cucumbers  for  pickles,  gather 
them  at  least  every  two  days.  Grade  them,  placing 
all  of  about  the  same  size  together.  These  may  be 
pickled  at  home,  or  if  you  live  near  a  pickle  factory 
you  will  probably  find  a  good  market  for  them. 

Record.  Keep  a  record  similar  to  the  one  sug- 
gested for  tomatoes.  Estimate  their  value  by  the 
dozen  instead  of  by  the  pound. 

Experiment.  1.  Try  two  or  three  varieties  keeping 
separate  accounts  to  see  which  is  most  profitable, 

2.  Plant  an  equal  number  of  mound  and  level  hills 
and  determine  which  gives  the  better  results. 

PROJECT  six 

BEANS  AND  PEAS 

Material.  Two  or  three  different  kinds  of  beans; 
box  of  soil  or  sand;  seed  catalogues. 


GARDEN  STUDIES  AND  HOME  PROJECTS 


169 


Study.  Soak  some  beans  of  any  variety  over  night. 
Compare  a  soaked  specimen  with  a  dry  one  and  note 
changes  that  have  taken  place.  How  many  distinct 
parts  do  you  find  in  the  bean? 

What  will  each  part  produce  when  the  bean  ger- 
minates and  grows!  To  an- 
swer this  question  plant  a 
number  of  seeds  in  a  small  box 
containing  soil.  Put  in  a  warm 
place,  the  temperature  of  the 
room  is  all  right,  and  keep 
moist.  Watch  for  the  appear- 
ance of  the  plants.  How  do 
they  break  through  the  soil? 
.Dig  up  one  seed  just  as  soon  as 

the  cotyledons  are  out  of  the  Fig  29  Bean  geed  and 
ground.  Describe  the  root  as  ^edjfg-  A  One  cotyledon; 

B,    Hypocotyl    and    radicle; 

to  color,  length  and  beginnings     C'    The   cotyledons    spread 

open;    D,    A    small   part    ot 

of    branches.      What    part    of     hypocotyl;  E,  Plumule;  F, 

Cotyledons  on  growing  seed- 

the  Seed  produced  the  root?  ling;   G,  Plumule  developed 

,.,,,,  into  first  pair  of  leaves;  H, 

Keep     the     plants     till     they       Root  developed  from  the  tip 
.,  .      ,          ,  .    ,        of  the  hypocotyl,  the  radicle. 

are  two  or  three  inches  high 

and  note  all  the  changes  that  take  place.  What 
finally  becomes  of  the  cotyledons?  What  value  are 
they  to  the  plant?  What  produces  the  first  true 
leaves?  When  do  the  next  leaves  appear?  Dig- 
up  another  plant  to  discover  any  additional  facts 


170  STUDIES  IN  SCIENCE 

concerning  the  roots.  Look  in  your  seed  catalogues 
for  the  classes  of  beans  that  are  listed.  Determine 
how  each  kind  is  supposed  to  be  used. 

Discussion.  You  found  your  bean  seed  made  up 
of  three  distinct  parts  besides  the  cover  or  seed  coat. 
The  thick  cotyledons  contain  food  for  the  growth  of 
the  little  plant.  You  noticed  that  they  changed  in 
form  and  color;  that  is,  they  really  grew  a  little  them- 
selves, but  after  most  of  the  food  in  them  was  used 
they  dropped  off.  They  are  sometimes  called  seed- 
leaves.  The  lower  end  of  the  hypocotyl  produced  the 
root;  the  upper  part  produced  part  of  the  stem. 

How  long  beans  have  been  used  as  food  no  one 
knows,  but  you  will  be  interested  to  learn  that  most 
of  the  species  of  beans  that  we  grow  are  natives  of 
America. 

Seed  men  usually  classify  their  beans  into  string 
or  pod  beans,  shell  beans,  and  dry  beans. 

Of  the  string  beans  the  entire  fruit  or  pod  with  the 
seeds  is  eaten.  Shell  beans  are  removed  from  the  pod 
and  eaten  while  immature.  Dry  beans  are  ripened 
seeds  that  may  be  kept  for  months  or  even  years. 

Decide  first  what  kind  of  beans  you  wish  to  grow. 
If  you  wish  them  for  market  or  table  use  early  in 
the  summer,  choose  string  varieties;  if  for  market 
or  use  in  the  late  summer  or  fall,  choose  some  variety 
of  shell  bean.  Nothing  gives  quite  as  good  results  at 


GARDEN  STUDIES  AND  HOME  PROJECTS  171 

this  time  as  lima  beans.  Some  of  the  shell  beans 
may  be  allowed  to  mature  and  may  then  be  used  as 
dry  beans.  The  navy  beans  are  the  best  and  most 
productive  of  the  dry  bean  group. 

Planting,     Wait  until  all  danger  of  frost  is  past 
and  the  soil  is  warm. 


Space  between 
Space  between  rows:  .     t  .  Depth: 

Bush  beans,  either  string  or 

dry,  2  feet.  3  to  4  inches.  1  to  2  inches  ac- 

cording to  size. 

Pole  beans,  2'/o  to  3  feet.  4  to  6  inches.        2  inches. 


If  you  wish  a  succession  of  string  beans,  plant 
some  every  two  or  three  weeks.  You  may  plan  to  use 
the  space  in  which  you  have  grown  early  crops  of  let- 
tuce or  radishes  for  your  late  beans. 

Harvesting,  marketing  and  canning.  String  beans 
are  ready  for  use  when  the  pod  snaps  easily.  They 
are  sold  by  the  pound  or  quart  measure.  Good  yield- 
ing varieties  bring  a  good  profit.  The  pole  limas 
yield  better  than  bush  varieties.  They  sell  exceed- 
ingly well  when  picked  and  shelled  green.  If  you 
have  more  than  you  can  market  in  this  way,  let  them 
mature  and  sell  them  as  dry  beans. 

All  kinds  of  string  and  shell  beans  may  be  canned 
by  the  cold  pack  or  hot  water  bath  method.  When 
the  beans  are  cleaned  and  ready,  dip  into  boiling 


172  STUDIES  IN  SCIENCE 

water,  allowing  them  to  remain  three  minutes.  Re- 
move and  put  into  cold  water.  Pack  into  jars,  add 
one  level  teaspoonful  of  salt  to  a  quart  and  enough 
hot  water  to  fill  the  jar.  Put  on  the  rubber  and  par- 
tially fasten  the  cover.  Place  the  jars  on  the  false 
bottom  of  the  boiler  and  pour  in  cold  water  till  it 
stands  two  inches  above  the  jars.  Allow  them  to  boil 
one  and  one-half  hours.  Remove  from  the  boiler, 
tighten  the  cover,  and  invert  to  cool. 

Keep  a  record  of  your  bean  project. 

Experiment.  Test  two  or  three  different  varieties 
of  string  beans  to  determine  which  gives  best  results. 

Canning.  Besides  the  vegetables  discussed  in  these 
projects,  many  others  that  you  grow  may  be  preserved 
for  future  use  by  canning.  The  purpose  of  boiling 
before  canning  is  to  sterilize  the  vegetables  so  per- 
fectly that  no  bacteria  will  be  left  to  grow  and  mul- 
tiply and  thus  cause  souring  and  decay.  Some  vege- 
tables, notably  tomatoes,  which  contain  considerable 
acid,  are  very  easily  kept  in  cans.  The  reason  for 
this  is  that  bacteria  do  not  thrive  well  in  an  acid 
medium.  Most  fruits  contain  some  acid  and  are 
more  easily  preserved  by  canning  than  vegetables. 
In  order  to  kill  all  the  bacteria  in  vegetables  which 
do  not  have  much  acid,  they  must  be  subjected  to 
heat  for  a  long  period.  In  the  home  the  most  com- 
mon method  of  canning  is  called  the  hot  water  bath. 


GARDEN  STUDIES  AND  HOME  PROJECTS  173 

For  this  a  large  kettle  or  boiler  may  be  used,  a  false 
bottom  may  be  made  out  of  wood,  two  pieces  of  two 
by  fours  with  slats  nailed  across  them.  A  wire  rack 
which  may  be  purchased  for  ten  or  fifteen  cents  is 
more  satisfactory.  Wire  racks  for  individual  jars 
may  be  bought  for  ten  cents  apiece.  The  steps  in 
canning  are  as  follows: 

1.  Can  vegetables  as  soon  as  possible  after  taking 
them  from  the  garden. 

2.  Have  vegetables  and  jars  perfectly  clean. 

3.  Blanch   the   vegetables.      This   means   plunging 
into  boiling  water  for  a  definite  period.    A  wire  bas- 
ket may  be  used,  or  they  may  be  tied  up  in  a  square 
of  cheese  cloth.     This   preserves   the   color,   hardens 
the  tissues,  and  kills  any  baceteria  that  may  be  on 
the  outside. 

4.  Plunge  into  cold  water  leaving  but  a  moment. 

5.  Pack  into  jars.     Put  a  teaspoonful  of  salt  into 
each  quart,  then  fill  to  the  top  with  hot  water. 

6.  Put  on  the  rubber  and  the  lid.     Do  not  screw 
the  lid  tight. 

7.  Put  the  jar  into  the  heater  in  cold  or  slightly 
warm  water.     Add  water  till  the  tops   of  the  jars 
are  covered  about  two  inches. 

8.  Boil  the  necessary  number  of  minutes. 

9.  Remove  from  the  water,  tighten  the  covers  and 
invert  to  cool. 


174 


STUDIES  IN  SCIENCE 


The  following  is  a  time-table  taken  from  the  sup- 
plement to  Farmers'  Bulletin,  No.  521,  Washington, 
D.  0.: 


TIME-TABLE 

To  be  followed  in  the  use  of  the  four  different  types  of  portable 
home  canners.  The  hot  water  bath  outfit  is  the  wash  boiler,  lard  tin 
or  pail  with  a  false  bottom. 


Hot  water  Water  seal  Steam 

Steam 

Blanch 

bath 

outfit 

pressure 

pressure 

or 

outfit  at 

above 

cooker 

cooker 

scald 

212°F. 

212°F. 

5  Ib. 

10  Ib. 

Minutes 

Minutes 

Minutes 

Minutes 

Minutes 

Apples  (whole)    

2 

20 

15 

12 

6 

Apples   (sliced)    

2 

15 

13 

10 

6 

Apricots   

1-2 

15 

12 

12 

6 

Asparagus    

5-10 

60 

60 

40 

30 

Beans,  (lima  and  string) 

5 

90 

60 

60 

30 

Beets  

G 

90 

75 

60 

40 

Blackberries    

12 

10 

6 

3 

Blueberries    

10 

8 

6 

3 

Cherries   

15 

12 

10 

5 

Corn   (without  acids).. 

5-15 

240 

180 

90 

60 

Grapes    

15 

15 

10 

6 

Grape  juice  

15 

15 

10 

5 

Hominy    

60 

50 

40 

35 

Huckleberries    

10 

8 

6 

3 

Okra    

5 

60 

60 

40 

30 

Okra  and  tomatoes  ..... 

50 

50 

40 

30 

Oysters   

50 

50 

40 

30 

Parsnips  

90 

60 

40 

30 

Peas  (garden  and 

English)     

5 

90 

80 

60 

40 

Pineapples  

30 

25 

10 

10 

Peaches    

1-2 

15 

12 

10 

5 

Pears  and  plums  

1-2 

15 

15 

10 

6 

Pumpkins    

5 

60 

60 

45 

35 

GARDEN  STUDIES  AND  HOME  PROJECTS 


175 


Hot  water  Water  seal  Steam     Steam 


Blanch  bath 

or  outfit  at 

scald  212  °F. 

Minutes  Minutes 

Raspberries 15 

Sauerkraut    50 

Sausage    60 

Sweet  potatoes 5  90 

Strawberries   15 

Squash    5  60 

Succotash    60 

Tomatoes    1-2  22 

Tomatoes   and   corn 80 

Tomato  juice    20 

Turnips    6  90 

Quince    2  30 

Fish,  pork  200 

Chicken,  beef   250 

Figs 30 

Spinach    5-10  60 

Other  greens 5-10  90 

Rhubarb   '. 1-3  15 

Egg  plant   5  60 

Carrots   5  .         60 

Cauliflower    .                   .5  60 


outfit    pressure  pressure 

above      cooker     cooker 

212°F.       5  Ib.        10  Ib. 

Minutes  Minutes  Minutes 


12 

50 
60 
75 
12 
60 
€0 
20 
70 
20 
75 
25 
200 
240 
20 
60 
90 
15 
50 
60 
60 


8 

40 

40 

60 

8 

45 
40 
10 
60 
15 
60 
15 
120 
180 
10 
40 
60 
10 
45 
45 
40 


5 

25 
35 
40 

5 

35 
30 

6 

40 
10 
40 
10 
60 
40 

5 

30 
40 

5 

30 
30 
30 


Size  of  jar.  When  cooking  products  in  pint  or 
half -pint  jars,  deduct  3  or  4  minutes  from  time  given 
above.  When  cooking  in  two-quart  jars,  add  3  or  4 
minutes  to  time.  The  estimate  given  is  for  quart  jars. 


CHAPTER  XI 

FARM  CROPS  AND  HOME  PROJECTS 

If  you  live  in  the  country  you  will  probably  want 
to  undertake  some  agricultural  projects  as  well  as 
to  raise  vegetables  or  flowers.  Any  farm  crop  that 
can  be  grown  in  your  community  will  make  a  project 
worth  while.  You  will  want  to  find  out  something 
about  the  habits  of  the  plants  you  decide  to  grow,  for 
your  projects  should  help  you  to  discover  for  your- 
self some  of  the  truths  and  underlying  principles  of 
life  as  well  as  teach  you  how  to  grow  crops  for  profit. 

PROJECT  SEVEN 

CORN 

Material.  Grains  or  corn,  flats,  plates,  and  muslin 
for  germination  tests. 

The  kernel.  Put  a  number  of  corn  kernels  into 
slightly  warm  water  and  let  them  soak  over  night. 
Examine  a  dry  grain.  What  is  the  shape  at  the  tip? 
Is  the  crown  dented  or  smooth  ?  How  do  the  flat  sides 
differ?  Study  a  soaked  specimen.  How  do  you 
account  for  the  changes  that  have  taken  place?  Care- 

176 


FARM  CROPS  AND  HOME  PROJECTS 


177 


wjCrown- 
llStarcbi 


Horny- 
Starch 


fully  remove  the  covering  from  a  soaked  grain.  Look- 
ing at  the  flat  sides  decide  how  many  distinct  parts 
there  are.  The  oval  shaped  portion  which  is  light 
gray  in  color  is  the  embryo  or  germ.  With  a  pen- 
knife remove  the  entire  embryo  using  care  not  to  tear 
it.  Lay  the  rest  of  the  grain  aside  and  examine  the 
embryo.  The  main 
part,  is  the  cotyledon. 
On  the  upper  side  of 
the  cotyledon  find  an 
indistinct  slit.  Pull  it 
gently  apart  length- 
wise. What  do  you 
find  on  the  inside? 
This  rod-like  body  is 
the  tiny  plantlet.  It  is 
sometimes  called  the 
germ.  The  end  toward 
the  crown  of  the  grain 
is  called  the  plumule. 
The  other  end  is  the 
hypocotyl. 

Experiment.  Which  end  will  make  the  root;  which 
the  shoot?  Place  several  soaked  grains  on  a  piece 
of  moist  blotting  paper  or  sand.  Turn  a  tumbler  or 
cup  over  them  in  order  to  retain  the  moisture.  A 
moist  piece  of  cloth  will  serve  as  well  as  blotting 


Imbrs 
Stem  j 

Embryo./ 
Boot    f 


Fig.  30. 

corn. 


Structure  of  .a  kernel  of 


178  STUDIES  IN  SCIENCE 

paper.  Keep  in  a  warm  place.  Examine  after  three 
or  four  days. 

Which  grows  more  rapidly  at  first,  the  root  or  the 
shoot?  Make  a  drawing  of  the  young  plant  and  ker- 
nel. On  one  side  name  the  parts  of  the  embryo;  on 
the  other  the  parts  of  the  plant.  See  Fig.  30. 

Endosperm.  Examine  the  portion  of  the  grain  that 
was  laid  aside.  This  is  called  the  endosperm.  How 
does  it  compare  in  size  with  the  embryo?  Take  a 
fresh  grain  and  cut  it  in  two  lengthwise  across  the 
flat  surface.  Is  the  endosperm  the  same  kind  of 
material  throughout?  How  many  different  kinds 
do  you  find? 

The  function  of  the  endosperm  is  to  furnish  food 
to  the  plant.  To  what  extent  is  the  plant  dependent 
upon  this  food  supply? 

Experiment.  Remove  the  embryo  from  a  number 
of  seeds.  Plant  them  in  soil  in  a  flower  pot  or  can. 
Place  in  a  warm  temperature  and  keep  watered.  In 
another  pot  plant  the  same  number  of  whole  grains. 
Let  them  grow  side  by  side  for  several  weeks  until 
you  can  decide  how  great  the  food  value  of  the  endo- 
sperm is.  After  four  or  five  weeks  dig  up  a  plant  that 
grew  from  an  entire  grain  and  examine  the  endosperm 
to  see  what  is  left.  In  what  form,  solid  or  liquid, 
do  you  find  the  starchy  food  material  that  the  plant 
is  using?  Where  does  the  plant  get  food  for  growth 


FARM  CROPS  AND  HOME  PROJECTS 


179 


when  the  endosperm  is  used  up?    See  Leaves,  page  38. 

Germination  test.  One  of  the  most  important 
things  to  do,  if  you  are  to  raise  corn,  is  to  make  a 
test  of  your  seed  to  see  whether  or  not  it  will  grow. 
There  are  several  ways  to  do  this.  The  following 
plan  is  a  good  one: 

Make  a  shallow  box  or  flat  three  or  four  inches 
deep.  Place  about  two  inches  of  clean,  moist  sand 
in  the  bottom.  Other  soil  will  do  equally  well  if  sand 


Fig.  31.     Corn  seed  tester. 

cannot  be  procured.  With  a  piece  of  board  make 
the  surface  very  smooth.  With  a  sharp  stick  or  the 
end  of  a  ruler  divide  the  surface  into  squares  two  and 
a  half  or  three  inches  each  way.  Number  the  squares 
from  left  to  right  beginning  in  the  upper  left-hand 
corner.  See  Fig.  31. 

The  next  step  is  to  get  the  corn  ready  for  the  box. 
Six  grains  from  each  ear  should  be  tested.  Take  two 
grains  from  near  the  butt  on  different  sides  of  the 


180 


STUDIES  IN  SCIENCE 


first  ear.  (Do  not  use  the*  ill-formed  grains.)  Take 
two  from  the  middle  and  two  from  near  the  tip.  Press 
them  slightly  into  the  sand  with  the  germ  side  up. 
Number  the  ear  1.  This  may  be  done  by  sharpening 
a  small  piece  of  shingle  or  other  thin  board,  putting 
the  number  on  it  and  sticking  it  into  the  pith  at  the 
butt  of  the  ear.  Remove  six  grains  from  another  ear 
in  the  same  way,  number,  and  continue  until  all  the 
squares  are  full  of  sample  grains.  Lay  the  ears  aside 
where  they  will  not  be  disturbed.  To  keep  the  grains 
moist,  place  a  piece  of  old  muslin  or  any  cotton  cloth 
over  them  and  put  about  two  inches  of  moist  sand 
on*  top.  Place  in  a  warm  temperature  and  keep  moist. 

GERMINATION  TEST  OF  CORN 


Ear 

Vig. 

Weak 

Failure 

Per  cent 

No.  1 

6 

100 

No.  2 

2 

4 

33^ 

No.  3 

1 

5 

00 

No.  4 

5 

1                      83^ 

The  germination  box  will  be  ready  for  examination 
in  four  or  five  days.  Begin  at  one  end  and  carefully 
roll  back  the  cloth  so  as  not  to  disturb  the  grains. 
Now  arrange  a  table  of  five  columns  and  place  the 
record  of  the  test  in  this.  In  the  table  the  first  column 
indicates  the  number  of  the  ear.  Vig.  stands  for 
vigorous.  The  other  terms  explain  themselves.  In 
the  table  ear  No.  1  shows  that  all  six  grains  have 


FARM  CROPS  AND  HOME  PROJECTS  181 

sprouted  vigorously  and  the  per  cent  is  of  course  100. 
Ear  No.  2  has  two  vigorous  sprouts  and  four  failures, 
hence  is  recorded  as  33  1/3  per  cent.  When  the 
entire  box  has  been  checked  up  in  this  fashion,  it 
will  be  easy  to  see  which  ears  should  be  kept  for 
planting  and  which  discarded.  What  per  cent  of  a 
perfect  stand  of  corn  would  you  expect  to  get  from 
ear  No.  2!  From  ear  No.  3 1  etc. 

Experiment.  Effect  of  temperature  upon  germina- 
tion. 

• 

Place  grains  from  the  same  ear  in  groups  of  three 
or  four  on  moist  cloth,  blotting  paper  or  sand.  Put 
one  group  in  a  refrigerator  or  other  very  cool  place, 
another  in  a  moderate  temperature,  and  the  third 
in  a  very  warm  place.  If  possible  test  the  tempera- 
ture of  each  place  with  a  thermometer.  Watch  care- 
fully for  results.  What  is  your  decision  as  to  the 
wisdom  of  planting  corn  before  the  soil  is  warm  in 
the  spring! 

Preparation  of  seed-bed.  What  implements  do  you 
use  in  getting  your  plot  or  field  ready  for  the  seed? 
If  the  ground  was  plowed  in  the  fall  it  should  be 
disced  and  harrowed,  perhaps  rolled  in  the  spring. 
It  is  important  that  the  seed-bed  be  mellow  and  well 
pulverized. 

Planting.  You  must  consider  the  following  points 
in  planting: 


382  STUDIES  IN  SCIENCE 

Distance  apart  of  rows :  This  varies  in  different 
localities  from  3  to  4  feet,  depending  upon  the  rich- 
ness of  the  soil.  In  the  corn  belt  of  the  Middle  West 
the  regulation  distance  is  3%  feet. 

Distance  apart  of  hills:  This  is  usually  the  same 
as  that  of  the  rows. 

Depth  to  plant:  This  depends  somewhat  upon  the 
condition  of  the  soil.  The  usual  depth  is  from  one 
and  a  half  to  two  inches. 

Firming  the  soil:  If  you  use  a  corn  planter  and 
check  row,  all  of  the  above  points  will  be  settled  for 
you.  If  you  plant  by  hand,  you  should  firm  the  soil 
over  the  seeds  with  the  back  of  the  hoe. 

You  may  live  in  a  region  where  corn  is  planted  in 
drills  instead  of  hills.  The  drills  are  from  3  to  3% 
feet  apart;  the  grains  are  planted  from  10  to  14 
inches  apart. 

Cultivating.  What  is  the  purpose  of  cultivating 
corn!  You  have  only  to  think  of  your  study  of  weeds 
and  of  soil  water  to  answer  this  question.  The  depth 
to  cultivate  depends  upon  the  condition  of  the  soil. 
A  deep  mellow  soil  may  be  cultivated  somewhat 
deeper  than  a  compact  very  moist  soil.  From  your 
study  of  corn  roots  you  have  learned  that  too  deep 
cultivation  will  destroy  many  of  the  small  roots  near 
the  surface  and  injure  your  prospect  for  a  good  yield 
of  corn.  It  is  usually  better  to  keep  the  field  as  level 


FARM  CROPS  AND  HOME  PROJECTS  183 

as  possible  rather  than  to  throw  the  soil  up  around 
the  hills.  You  can  keep  a  better  soil  mulch  to  con- 
serve moisture  with  level  cultivation. 

Keep  the  following  record  of  your  corn  project: 

1.  Size  of  plot. 

2.  Crop  raised  on  plot  last  year. 

3.  Time  of  planting.     Time  of  harvesting.    Variety  of  corn.     Dis- 
posal of  crop. 

4.  Expenditures. 

a.  Cost  of  seed. 

b.  Rental  value  of  plot. 

c.  Cost  of  labor.     (Keep  record  of  hours  spent  and  calculate 
at  price  paid  for  such  work.) 

d.  Cost  of  fertilizer. 

5.  Receipts. 

a.  Yield  of  plot  in  bushels. 

b.  Value  when  sold  or  used. 

c.  Value  of  other  parts  of  the  plant  if  these  are  used  for  feed. 

6.  Profits. 

a.  Yield  of  plot. 

b.  Value  at  market  price. 

c.  Net  profits. 

d.  Net  profit  per  acre. 

PROJECT  EIGHT 

OATS 

Material.  Samples  of  oat  seeds,  plates  or  boxes  for 
making  germination  tests. 

Study.  If  you  live  in  a  region  where  oats  are 
grown  you  may  plan  to  raise  a  crop  of  your  own. 
What  time  of  year  are  oats  sown  in  your  community? 
Do  the  farmers  raise  a  larger  or  smaller  acreage  of 
oats  than  of  some  other  crop?  Find  out  the  names 


184  STUDIES  IN  SCIENCE 

oi  varieties  of  oats  grown.  How  do  you  account  for 
the  fact  that  oats  may  be  planted  so  much  earlier  in 
the  season  than  corn? 

The  grain.  Remove  the  chaffy  covering  from  a 
grain  and  note  the  size,  color,  and  shape.  Compare 
it  with  a  grain  of  wheat,  rye  and  barley.  Compare 
several  different  varieties  of  oats  with  each  other  as 
to  size  and  color. 

Purity  test.  Spread  out  a  small  quantity  of  your 
sample  upon  a  sheet  of  white  paper.  Look  closely  for 
foreign  bodies  of  any  kind.  Put  all  the  weed  seeds 
and  trash  in  one  pile  and  all  the  oats  in  another. 
About  what  part  of  your  sample  is  pure  oats!  How 
can  chaff  and  light  weed  seeds  be  removed  from  the 
oats!  If  you  have  a  fanning  mill,  run  the  oats 
through  it.  A  small  amount  may  be  cleaned  by  hold- 
ing it  high  in  the  air  on  a  windy  day  and  allowing 
it  to  fall  several  feet.  A  sheet  may  be  spread  down 
to  catch  it. 

Germination  test.  The  most  important  thing  to 
know  about  your  seed  oats  is  whether  or  not  nearly 
every  grain  will  germinate  and  grow.  There  is  only 
one  way  to  determine  this  and  that  is  by  making  a 
germination  test.  Count  out  one  hundred  seeds  from 
your  sample.  Place  some  moist  sand  or  other  soil 
in  a  dinner  plate  or  box.  Scatter  the  seeds  over  the 
sand,  not  allowing  any  two  to  touch.  Press  the  seed 


FARM  CROPS  AND  HOME  PROJECTS  185 

slightly  into  the  sand  but  do  not  cover.  Now  turn 
another  plate  over  this  one  or  cover  with  a  damp 
cloth.  Keep  moist. 

How  long  after  planting  before  the  first  sprouts 
appear!  Keep  watch  for  two  or  three  days.  How 
many  of  the  seeds  fail  to  sprout!  What  per  cent 
have  sprouted?  What  percentage  of  a  perfect  stand 
of  oats  would  you  expect  to  get  from  this  seed! 

Preparation  of  seed-bed.  The  preparation  of  the 
seed-bed  for  your  oats  plot  depends  upon  what  was 
raised  on  the  ground  last  year.  If  the  soil  was  well 
cultivated,  discing  or  harrowing  may  be  all  that  is 
necessary  now.  If  the  ground  is  hard  and  compact, 
it  should  be  plowed  and  harrowed. 

Planting.  What  methods  of  sowing  oats  are  prac- 
ticed in  your  neighborhood!  How  many  farmers  use 
drills!  How  many  use  broadcast  seeders!  How  much 
oats  will  be  required  to  plant  an  acre!  Some  farm- 
ers use  from  three  to  three  and  one-half  bushels. 
Others  claim  that  they  get  a  better  yield  by  sowing 
from  one  and  a  half  to  two  bushels. 

The  chief  rule  to  follow  as  to  time  of  planting  is 
to  sow  your  oats  in  the  spring  as  early  as  the  soil  can 
be  worked.  In  the  South  they  are  sown  in  the  fall 
and  are  known  as  winter  oats. 

Oats  belonged  originally  in  a  cold  climate.  It  is  a 
crop  of  northern  regions,  especially  of  Sweden  and 


186  STUDIES  IN  SCIENCE 

Northern  Bussia.  Some  of  our  best  varieties  origin- 
ated in  these  countries.  This  is  the  reason  we  plant 
them  so  early  in  the  spring.  Watch  to  see  whether 
a  frost  injures  the  young  plants. 

Treating  for  smut.  Smut  is  a  disease  which  attacks 
oats  decreasing  the  yield  in  many  places  from  15  to 
25  per  cent.  You  can  prevent  smut  by  treating  the 
seed  with  formalin.  (See  page  237.)  You  may  be 
interested  to  make  an  experiment.  Measure  off  two 
tracts  of  ground  of  exactly  the  same  dimensions.  In 
one  sow  oats  that  have  been  treated  with  formalin. 
In  the  other  sow  untreated  seeds.  When  the  plants 
are  heading  out  examine  them  for  smut  and  deter- 
mine whether  the  formalin  treatment  was  effective. 
If  possible  get  the  exact  yield  from  each  plot  and 
estimate  the  loss  per  acre  due  to  smut. 

Observation  of  growing  plants.  Watch  the  habit  of 
growth  of  the  oats  plants.  When  they  are  six  weeks 
or  two  months  old  examine  them  and  determine  how 
many  stems  grow  from  one  root.  What  kind  of  leaves 
has  the  plant!  Note  the  plants  when  they  blossom 
or  head  out.  This  kind  of  branching  is  called  a 
panicle.  If  the  branches  are  all  on  one  side,  it  is 
called  "side  oats."  Make  a  careful  study  of  the 
panicle.  Note  where  the  grains  are  attached.  Look 
in  the  head  for  grains  of  different  sizes. 

When  your  crop  is  about  ready  to  harvest  look 


FARM  CROPS  AND  HOME  PROJECTS 

through  it  for  heads  that  seem  superior  to  the  others 
in  size  and  weight.  If  you  are  interested  in  breeding 
up  your  oats  to  a  better  yield,  cut  out  these  heads, 
thresh  them  and  plant  them  in  a  plot  by  themselves 
next  year.  You  will  in  this  way  get  seed  enough  to 
plant  several  acres  in  a  few  years  and  perhaps 
increase  the  yield  many  per  cent. 

Keep  the  following  record  of  your  oat  project: 

1.  Date  of  planting. 

2.  Date  of  harvesting. 

3.  Yield  of  plot. 

4.  Yield  per  acre. 

5.  Expenditures. 

a.  Value  of  seed. 

b.  Rent  of  plot. 

c.  Cost  of  labor. 

d.  Cost  of  threshing. 

6.  Receipts. 

a.  Value  of  oats  at  current  price. 

b.  Value  of  straw. 

c.  Net  profits. 

d.  Net  profit  per  acre. 

PROJECT  NINE 

WHEAT 

If  you  planted  a  plot  of  wrlieat  in  the  fall,  make 
field  observations  of  the  plants.  Note  the  condition 
of  the  field  at  the  close  of  winter.  Has  any  part  of  it 
been  killed?  Dig  up  a  plant  and  note  the  length  of 
the  root  system.  If  any  new  leaves  have  developed 


188  STUDIES  IN  SCIENCE 

this  spring,  determine  from  what  part  of  the  plant 
they  grew.  Watch  occasionally  the  development  and 
growth  of  the  entire  plant,  especially  of  the  flowering 
heads,  until  harvest.  When  does  the  head  first 
appear?  Note  the  change  of  color  that  takes  place 
as  the  wheat  matures. 

Keep  a  record  of  your  wheat  plot  using  the  items 
suggested  for  oats. 


CHAPTER  XII 


TREES 

Flowers  and  leaves.  Keep  a  simple  flower  record 
of  the  trees  of  your  community.  Note  the  date  of 
blossoming;  the  color  and  kind  of  flowers;  date  of 

opening  of  leaf  buds.  What 
trees  have  separate  flower 
and  leaf  buds !  Which  have 
a  combination  of  the  two! 
Some  of  the  maples  and 
elms  blossom  very  early, 
long  before  the  leaf  buds 
open.  In  the  South  the 
swamp  maple  begins  to 
open  its  beautiful  red  flow- 
ers the  latter  part  of  Febru- 
ary or  the  first  of  March. 
Farther  north  the  silver 
and  red  maples,  as  well  as 


Fig.     32.       Flowers     of 
American   Elm   in  April. 


the 


members  of  the  elm  family, 
blossom  the  latter  part  of  March  or  the  first  of  April. 
These  blossoms  while  very  small  are  wonderfully  in- 
teresting and  should  be  studied  at  close  range.  Some 

189 


190 


STUDIES  IN  SCIENCE 


of  them  are  perfect,  having  both  stamens  and  pistils; 
this  is  always  true  of  the  elms.  Other  trees  have  two 
distinct  kinds  of  flowers,  staminate  and  pistillate. 
None  of  these  early  flowers  have  brightly  colored 
petals. 

The  growth  of  trees.  Watch  terminal  buds  of  sev- 
eral different  species  of  trees  as  they  open  and 
develop.  How  long  is  the  new  part  of  the  twig  by 

. ,     the      time      the 

leaves  are  well 
open?  Where  do 
new  leaves  con- 
tinue to  appear! 
Compare  several 
species  as  to  the 
rapidity  with 
which  the  twigs 
lengthen.  Watch 
also  the  develop- 
ment of  lateral 
buds.  What  do 
they  produce? 


Fig.  33. 
May. 


Fruit  of  the  American  Elm  m 


Compare  the 
growth  of  twigs  from  lateral  with  those  from  terminal 
buds. 

What  other  growth  does  a  tree  make  besides  put- 
ting out  new   twigs   and  lengthening   its   branches? 


TREES 


191 


To  answer  this  question  you  should  have  some  cross 
sections  of  twigs  and  branches.  If  people  in  the 
neighborhood  are  pruning  their  trees  make  some 
sections  of  different  sized  branches.  Each  section 
should  be  cut  straight  across  and  should  be  an  inch 
or  two  in  length.  If  some  one  cuts  down  a  tree  get 
a  few  large  sections.  These  may  be  kept  in  the  school 
room  for  years. 

Besides  the  above  make  some  sections  of  a  one, 
two,  and  three-year-old  twig.  Willow  or  poplar  are 
good  for  this  study.  Ex- 
amine the  one-year  sec- 
tion first.  How  many 
distinct  structures  do 
you  find  ?  For  names  see 
Fig.  35.  Peel  the  bark 
from  some  of  the  fresh 
twigs.  How  does  the 
wood  underneath  look? 
Rub  your  finger  over  it. 

How  does  it  feel?     Ex-  Flowe™  of  the  Nor" 

amine  in  the  same  way 
the  inside  of  the  bark  that  you  removed. 

Compare  the  two  and  three-year-old  sections  with 
those  of  one  year,  noting  differences.  How  do  the 
oldest  sections  that  you  have  differ  from  the  younger 
ones?  What  do  the  rings  tell?  What  indications 


192  STUDIES  IN  SCIENCE 

are  there  that  the  tree  grew  faster  some  years  than 
others!  How  does  the  bark  on  the  young  stems 
differ  from  that  on  the  older  branches  or  the  trunk? 
Why  is  the  older  bark  so  rough  while  the  young 
twigs  are  smooth?  Examine  a  number  of  twigs  and 
branches  of  varying  ages  to  see  if  you  can  solve  this 
problem  for  yourself. 

Discussion.  The  growth  of  a  tree  is  not  limited 
to  the  making  of  new  twigs  and  the  lengthening  of 
the  old  ones.  From  your  study  of  the  cross  section 


Fig.  35.  1.  Cross-section  of  a  twig  one-year-old,  a,  Outer  bark; 
b,  Inner  bark;  c,  Cambium  layer;  d,  Wood  layer;  e,  Pith.  2.  Cross- 
section  of  a  twig  two-years-old,  a  and  b  show  the  two  rings  of  wood 
growth. 

you  know  that  there  is  a  growth  in  thickness.  Each 
ring  of  wood  usually  shows  a  year's  growth.  The 
growth  takes  place  in  the  sticky  layer  that  you  found 
between  the  bark  and  the  wood.  This  is  known  as  the 
cambium.  Not  only  does  a  new  layer  of  wood  grow 
here  each  year,  but  a  new  layer  of  bark  also. 

The  outer  layer  of  bark  does  not  grow,  and  when 
new  layers  of  wood  and  bark  grow  on  the  inside  the 
outside  has  to  stretch.  After  a  time  it  can  stretch 


TREES  183 

no  more  and  then  it  cracks.  If  you  look  at  branches 
of  different  ages  you  see  that  the  cracks  grow  deeper 
and  more  numerous  year  by  year  until  finally  there 
are  the  deep  fissures  that  you  find  in  the  oldest  part 
of  the  tree. 

Do  you  know  any  tree  whose  bark  on  the  trunk 
remains   smooth  until  the  tree  is  quite  old?     What 
must   be    true   of 
the  growth  when 
this  is   the  case? 
The  bark  and  the 
wood    grow    at 
about    the     same 


Fig.   36.     Pistillate  flowers  of  silver  maple. 

rate  for  a  number 

of  years.  The  wild  cherry  and  the  white  birch  are 
good  examples  of  this.  For  a  long  time  the  trunk  is 
as  smooth  as  the  branches,  then  little  by  little  the 
bark  cracks  and  scales,  making  quite  a  rough  surface 
when  the  tree  is  old. 

If  you  have  a  section  of  a  large  tree  you  can  prob- 
ably see  a  distinct  difference  between  the  wood  at 
the  center  and  that  toward  the  outside.  The  inside 
portion  is  called  heartwood;  the  outside,  sapwood. 
The  heartwood,  after  a  number  of  years,  becomes  dry 
and  hard.  It  is  really  dead  but  it  still  helps  to  sup- 
port and  strengthen  the  tree.  However,  trees  may 
live  a  number  of  years  with  much  of  the  heartwood 


194 


STUDIES  IN  SCIENCE 


decayed.  You  liave  no  doubt  seen  living  trees  that 
were  quite  hollow.  Name  one  or  more  species  of  trees 
in  which  the  heartwood  is  likely  to  decay  while  the 
tree  continues  to  grow. 

The  food  of  trees.  Since  trees  grow  they  must 
have  food.  If  you  bore  a  small  hole  in  a  map]e  tree 
in  the  early  spring*,  or  break  the  tip  off  a  branch,  sap 
runs  out.  If  you  taste  this  sap  you  find  that  it  is 
sweet.  Where  did  it  get  the  sugar  that  is  in  it  ?  From 

your  fall  study  you  know  it 
was  manufactured  last  summer 
by  the  leaves  and  was  stored  in 
the  tree  during  the  winter. 
You  may  think  of  the  leaves  of 
trees  as  factories  that  make 
food  for  the  entire  tree.  The 
roots  take  in  water  and  some 
minerals  from  the  soil  which 
travel  upward  through  the 


Fig.  37.    staminate  flow-  stem  to  the  leaves ;  the  leaves 

ers  of  silver  maple. 

themselves  take  a,  gas,  carbon 

dioxide,  from  the  air,  and  with  these  raw  materials,  all 
day  long  in  the  sunlight  during  the  spring  and  sum- 
mer, they  manufacture  plant-food.  Some  of  this  is 
used  for  growth  during  the  summer,  but  much  of  it 
accumulates  in  the  twigs,  stems  and  roots  for  future 
use. 


TREES  19j 

Our  native  woods.  If  possible,  visit  a  native  woods. 
Stand  under  the  trees  and  look  up.  To  what  extent 
do  the  crowns  cover  the  overhead  space?  How  many 
different  kinds  of  trees  do  you  find!  Which  species 
are  largest!  Which  medium  in  size!  Note  the  sap- 
lings, trees  from  four  to  ten  or  even  fifteen  feet  in 
height.  Are  they  the  same  species  as  the  largest 
or  the  medium  size  trees!  How  numerous  are  the 
seedlings,  young  trees  not  more  than  three  feet  high! 
What  different  species  do  they  represent!  If  the 
woods  are  left  undisturbed,  what  species  will  be  most 
abundant  fifty  or  one  hundred  years  hence!  What 
shrubs  do  you  find  growing  under  the  trees!  What 
wild  flowers!  Examine  open  spaces.  Note  what 
plants  are  growing  there  that  are  not  found  in  the 
dense  woods.  How  do  you  account  for  the  difference! 

What  is  the  condition  of  fallen  logs  or  old  stumps! 
Look  for  branches  that  have  recently  fallen.  Exam- 
ine the  spots  on  the  trees  from  which  they  have 
dropped.  If  these  trees  are  used  for  lumber,  the  base 
of  every  branch  will  appear  as  a  knot  in  the  boards. 
From  what  kind  of  tree  can  clear  lumber,  that  is 
boards  free  from  knots,  be  obtained! 

What  use  is  made  of  wooded  regions  in  your  local- 
ity! How  many  are  pastured!  Do  the  stock  injure 
the  trees  in  any  way!  How  many  are  kept  as  wood- 
lots  by  their  owners!  What  different  wood  products 


]96  STUDIES  IN  SCIENCE 

may  a  wood-lot  well  cared  for  produce!  To  what 
extent  are  the  woods  in  your  part  of  the  state  disap- 
pearing? Are  there  any  tracts  in  your  county  that 
have  been  set  apart  for  the  use  of  the  public?  What 
do  you  think  of  the  plan  of  having  a  few  areas  of  our 
native  woods  in  every  county  preserved  for  all  time 
for  the  people?  They  could  be  used  as  recreation 
grounds  for  the  community,  but,  better  than  that, 
for  study  purposes  by  all  the  school  children. 

Forests  and  forestry.  We  usually  call  small  areas 
of  trees  woods  or  woodlands,  but  the  large  tracts 
which  are  used  for  lumbering  purposes  are  known  as 
forests.  Lumbermen  classify  the  forests  into  hard 
wood  and  soft  wood.  Hard  wood  forests  comprise 
the  broadleaf  trees  as  walnut,  maple,  oak,  birch  and 
mahogany.  Soft  wood  forests  are  the  cone  bearing 
trees  such  as  pines,  cedars  and  spruces.  Your  geog- 
raphy will  tell  you  where  these  various  forests  are 
found. 

Forests  have  many  enemies  such  as  fires,  insects, 
fungous  diseases  and  wasteful  methods  of  lumbering. 
The  art  of  cultivating,  managing  and  caring  for  for- 
ests is  known  as  forestry.  The  forestry  branch  of 
the  U.  S.  Department  of  Agriculture  has  given  much 
attention  in  recent  years  to  the  better  management 
and  care  of  our  great  forests.  It  tries  to  prevent 
fires,  to  combat  insect  pests,  and  to  introduce  the 


TREES  197 

best  methods  of  lumbering,  so  that  by  the  conserva- 
tion of  the  young  trees  the  lumbering  industry  may 
be  kept  permanent.  It  is  also  attempting  to  raise 
timber  crops  in  treeless  regions  of  the  West. 

Uses  of  trees.  What  are  trees  good  for?  You  have 
only  to  look  around  in  your  home  and  school  to 
realize  how  very  useful  trees  are.  Make  a  list  of  all 
the  things  in  and  about  your  home,  school,  church, 
stores,  street,  and  farm  that  are  made  wholly  or  in 
part  from  the  wood  of  trees.  Make  a  second  list 
which  includes  trees  that  furnish  food  of  some  kind. 
Make  a  third  list  in  which  you  include  the  value  of 
trees  in  affording  you  and  other  people  pleasure. 

The  first  and  second  lists  give  you  some  idea  of  the 
great  value  of  trees  in  the  industrial  world.  They 
not  only  furnish  quantities  of  food  and  the  vast 
amount  of  materials  used  in  buildings,  furniture, 
machinery,  paper,  etc.,  but  at  the  same  time  they 
afford  employment  to  thousands  of  people  in  lumber 
regions,  in  factories,  in  carpentry,  in  paper  mills, 
etc.  Your  geography  will  tell  you  something  of  the 
great  centers  of  these  activities. 

The  third  list  helps  you  to  appreciate  the  value 
of  trees  in  your  own  life.  They  afford  shade  and 
shelter,  provide  nesting  places  for  birds,  and  make 
our  homes,  public  school  grounds,  and  the  entire 
landscape  beautiful.  Why  do  artists  so  commonly 


198  STUDIES  IN  SCIENCE 

put  trees  into  pictures?    Where  are  trees  most  beau- 
tiful to  you! 

Trees  on  home  grounds.  Study  the  trees  about 
your  homes  and  other  places  in  your  neighborhood. 
How  many  of  them  are  native  trees!  How  did  they 
happen  to  be  there!  Did  they  grow  wild  or  were 
they  planted!  Which  of  them  do  you  like  best!  Is 
there  any  one  tree  in  the  neighborhood  that  you  con- 
sider especially  beautiful?  If  it  is  an  old  tree,  find 
out  all  you  can  about  its  history.  What  street  or 
road  has  the  most  beautiful  row  of  trees!  Which 
do  you  think  is  more  attractive,  a  street  planted  the 
entire  length  with  one  species  of  tree,  or  one  planted 
with  a  number  of  species! 

Select  the  home  in  your  community  that  has  its 
trees  arranged  to  give  the  most  beautiful  effect,  an 
effect  that  makes  the  trees  and  buildings  look  as  if 
they  belong  together. 

Planting  trees  on  home  grounds.  Trees  about  a 
home  may  add  much  or  little  to  its  attractiveness 
according  to  the  trees  used  and  the  manner  in  which 
they  are  set  out.  Simple  rules  to  follow  in  planting 
home  grounds  are:  1.  Choose  hardwood,  long  lived 
trees,  not  the  shorter  lived,  more  rapid  growers. 
With  a  few  rare  exceptions  choose  native  rather  than 
foreign  trees.  2.  Place  the  trees  at  the  sides  and 
rear  of  the  house,  not  in  front.  You  do  not  want 


TREES 


199 


them  to  screen  the  building,  but  rather  to  make  a 
background  and  natural  setting  for  it.  3.  Let  the 
height  of  the  building  help  to  determine  the  species 
of  trees  to  use.  Cottages  and  bungalows  to  make  a 
pleasing  landscape  picture  should  have  low  trees 


Fig.  38.     Spraying  large  trees. 

nearby.     On  the  other  hand,  high  buildings  require 
some  tall  trees  to  frame  them  in. 

Care  and  protection  of  trees.  You  should  be  inter- 
ested in  trying  to  keep  the  trees  in  your  community 
in  as  good  a  condition  as  possible.  Trees  need  care 
and  protection,  and  while  you  may  not  be  able  to 
do  much  active  work  you  can  do  something.  Make 
a  simple  survey  of  the  trees  in  your  block  or  district 


200  STUDIES  IN  SCIENCE 

to  find  out  whether  or  not  they  need  attention.  How 
many  do  you  find  that  have  been  injured  in  some  way! 
Determine,  if  possible,  what  caused  the  injury.  Are 
any  insects  feeding  upon  the  trees!  Look  on  the 
bark  for  scales.  Examine  the  old  trees  for  unhealthy 
conditions  as  shown  by  decaying  spots  or  fungous 
growths.  Look  for  dead  branches  that  should  be 
cut  out.  Do  you  find  guards  around  young  trees? 
Are  there  any  that  should  be  protected  in  this  way 
but  are  not!  Report  what  you  find  to  your  teacher 
or  to  the  officer  whose  business  it  is  to  look  after 
the  welfare  of  the  trees.  Another  thing  you  may  do 
is  to  be  careful  not  to  injure  trees  yourself.  Avoid 
swinging  on  young  trees  or  breaking  off  twigs  and 
branches.  You  may  help  to  work  up  a  sentiment  in 
your  neighborhood  that  will  go  far  toward  making 
other  people,  both  children  and  adults,  take  a  greater 
interest  in  caring  for  the  trees. 


PART  TWO 
FALL  STUDIES 

CHAPTER  XIII 

INSECTS 

Material.  Insects  of  the  garden,  orchard,  fields 
and  home;  wide-mouthed  bottles  or  tumblers;  several 
pint  and  quart  jars;  a  flower  pot  with  a  lantern  globe 
or  lamp  chimney;  a  wire  cage  or  vivarium;  a  small 
hand  lens. 

A  vivarium.  For  the  foundation  of  this  use  a 
shallow  box  a  foot  and  a  half  or  two  feet  long, 
six  inches  wide  and  three  inches  deep.  Nail  upright 
in  each  corner  a  flat  piece  of  board  fifteen  inches  high, 
about  an  inch  wide  and  half  an  inch  thick.  Com- 
plete the  frame  by  nailing  pieces  of  board  to  the  top 
of  the  uprights.  Cover  the  sides  with  wire  screen 
or  mosquito  netting,  and  place  a  board  or  pane  of 
glass  on  the  top  for  a  cover.  See  Fig.  39. 

A  simple  cage  may  be  made  from  an  ordinary  shoe 
box.  Cut  rectangular  pieces  out  of  the  top  and  bot- 
tom and  sew  in  wire  screening  or  mosquito  netting, 

201 


2012  STUDIES  IN  -SCIENCE 

tying  a  string  around  the  box  to  keep  the  lid  on. 
Stand  it  on  one  side  and  you  can  easily  watch  the 
movements  of  insects  within. 

If  you  wish  to  make  a  collection  of  insects,  a 
cyanide  jar  is  necessary.  To  make  one  place  five 
cents'  worth  of  cyanide  of  potassium  in  the  bottom  of 
a  wide  mouthed  bottle  or  pint  fruit  jar.  Handle  the 


Fig.  39.     A  vivarium  or  insect  cage  stocked  with  insects. 

cyanide  very  carefully;  do  not  touch  it  with  your 
fingers.  Make  a  stiff  paste  of  plaster  of  Paris  and 
water.  Pour  this  over  the  cyanide,  covering  it  about 
an  inch  or  an  inch  and  one-half  in  depth.  Allow  the 
bottle  to  stand  open  two  hours,  then  close  it  tightly 
and  keep  closed  except  when  putting  insects  in  or 
taking  them  out.  Label  the  jar  POISON. 

Garden  pests,     Make  a  list  of  all  the  insects  you 


INSECTS 


203 


have  found  in  your  garden  this  season.  Choose  for 
detailed  study  any  that  you  find  on  your  plants  now. 
The  cabbage  worm.  Look  on  cabbage  plants  for 
worms  or  larvae.  On  what  part  of  the  leaves  are 
they?  What  are  they  doing!  How  many  different 


Fig.  40.  The  common  cabbage  worm  (Pontia  rapae).  a,  Female 
butterfly;  b,  Egg;  c,  Larva,  or  worm,  in  natural  position  on  cabbago 
leaf;  d,  Suspended  chrysalis,  or  pupa. 

sizes  are  there?  Do  they  look  as  if  they  were  all  the 
same  species?  Collect  a  number  of  leaves  with  the 
worms  on  them  and  place  them  in  a  box  in  the  school 
room  for  further  study.  Look  carefully  at  one  larva 
and  note  everything  that  you  see.  Describe  the  body 


204  STUDIES  IN  SCIENCE 

covering.  What  is  the  number  of  feet?  How  do  the 
feet  on  different  parts  of  the  body  differ  from  one 
another?  What  are  the  uses  of  the  different  kinds! 

Watch  a  larva  feeding.  How  does  it  eat?  What 
kind  of  mouth  has  it?  Determine  this  by  observing 
the  partially  eaten  leaves.  Put  several  larvae  into 
a  box  or  insect  cage  and  give  them  fresh  leaves  every 
day.  Watch  for  changes.  Describe  the  new  form. 
This  is  called  a  pupa,  the  plural  is  pupce.  Deter- 
mine how  the  pupa  is  attached  to  the  box.  Examine 
it  with  your  lens  and  describe  what  you  see.  Keep 
the  box  with  the  pupae  so  that  you  may  later  see  the 
adult  insects. 

If  you  have  two  kinds  of  larvae  compare  them 
noting  differences.  How  do  they  differ  in  the  pupa 
stage  ? 

The  butterfly.  Watch  white  butterflies  hovering 
over  the  cabbage  plants.  What  do  they  seem  to  be 
doing?  Look  very  closely  on  the  leaves  especially 
on  the  under  side  for  eggs.  These  are  small  cream 
colored  specks  that  stand  up  on  end.  Examine  one 
with  your  lens  and  describe  it.  Capture  a  butterfly, 
place  it  in  a  clear  glass  bottle  and  note  its  colors,  the 
number  of  feet,  the  wings,  the  kind  of  antennae, 
(feelers)  and  the  mouth. 

Are  cabbage-worms  very  destructive?  What  meth- 
ods of  combating  them  do  you  know? 


INSECTS  205 

Discussion.  If  you  saw  all  the  legs  of  the  cab- 
bage-worm, you  noticed  three  pairs  of  rather  pointed 
ones  near  the  head,  four  pairs  of  wide  ones  near  the 
middle,  and  one  wide,  flat  pair  close  to  the  hind  part 
of  the  body.  The  three  near  the  head  are  called  true 
legs;  all  of  the  others  are  prop  legs.  The  prop  legs 
are  used  for  clinging  as  well  as  for  crawling. 

Cabbage-butterflies  lay  their  eggs  upon  cabbage 
leaves.  These  hatch  into  small  larvae  which  have 
jaws  or  biting  mouths  with  which  they  nibble  holes 
in  the  leaves.  When  they  are  ready  to  change  into 
pupae,  they  fasten  themselves  to  some  object  by 
means  of  a  few  silk  threads  bound  about  the  middle 
part  of  the  body.  Then  they  shed  their  skins  and 
become  pupae.  During  the  summer  and  early  fall 
the  insect  remains  in  the  pupa  stage  from  a  week  to 
ten  days.  Those  that  pupate  late  in  the  fall  remain 
in  this  stage  all  winter.  When  the  pupa  changes  to  a 
butterfly,  the  skin  splits  along  the  back  and  the  but- 
terfly emerges.  The  pupa  skin,  as  well  as  the  pupa 
itself,  is  often  called  a  chrysalis. 

If  you  had  two  kinds  of  larvae,  you  found  that 
the  one  with  prominent  sections,  when  it  went  into 
the  pupa  state,  spun  a  thin  white  cocoon  and  changed 
to  a  dark  brown  pupa.  This  larva  produces  a  cab- 
bage-moth instead  of  a  butterfly.  It  remains  in  the 
pupa  stage  about  ten  days  and  then  emerges,  a  small, 


20G  STUDIES  IN  SCIENCE 

dark-colored  moth,  the  kind  that  people  often  call 
moth  millers.  Compare  the  moth  with  the  butterfly 
noting  differences. 

Tomato-worm.  If  you  have  tomato  plants,  you  may 
find  larvae  of  the  tomato  sphinx-moth  on  them.  Study 
these  as  you  did  the  cabbage-worm.  If  you  wish  to 
watch  them  through  their  life  history,  you  must  pro- 
vide soil  in  which  they  may  pupate.  Fill  a  fruit  jar 
about  half  full  of  garden  soil.  Firm  it  down,  then 
place  the  worm  in  it  with  tomato  leaves  for  it  to 
feed  upon.  When  the  larva  is  ready  to  pupate  it 
pushes  down  into  the  soil,  makes  a  mud  cell  perfectly 
smooth  on  the  inside,  then  sheds  its  larva  skin  and 
becomes  a  pupa.  Sometimes  when  you  spade  up  your 
garden  in  the  spring,  you  find  the  brown  pupa  of 
the  tomato-worm.  It  has  a  loop  on  one  side  which 
resembles  a  handle.  This  is  a  case  for  the  long  suck- 
ing tube  of  the  moth.  Set  the  jar  in  which  the  worm 
has  pupated  in  a  cool  place  and  occasionally  moisten 
the  soil  a  little  especially  in  the  early  spring.  Place 
a  small  twig  in  the  jar  to  which  the  moth  may  cling 
when  it  emerges  from  the  ground.  These  moths 
appear  from  April  until  the  latter  part  of  May  or 
even  June,  depending  upon  the  latitude. 

You  have  probably  discovered  that  while  the  larvae 
of  moths  and  butterflies  have  biting  mouths  with 
which  they  eat  leaves,  the  adults  have  sucking  mouths 


INSECTS  207 

and  feed  upon  the  nectar  of  flowers.  Many  moths 
are  quite  as  beneficial  as  bees  in  carrying  pollen  from 
one  flower  to  another.  All  butterflies  and  moths  have 
the  same  kind  of  life  history  as  the  cabbage-worm 
and  the  tomato-worm.  They  have  four  distinct  stages : 
the  egg,  larva,  pupa  and  adult.  Insects  that  make 
this  complete  change  in  their  form  are  said  to  have 
complete  metamorphosis. 

Squash -bug.  Look  on  your  pumpkin  and  squash 
vines  for  a  flat,  dark  gray  insect  a  little  more  than 
half  an  inch  in  length.  Where  on  the  plants  do  you 
find  them?  What  are  they  doing?  Visit  the  plants 
early  in  the  morning,  again  during  the  warm  part 
of  the  day,  and  in  the  evening.  How  do  the  insects 
differ  in  their  behavior  at  these  different  times  ?  How 
many  stages  of  development  do  you  find  among  them? 
How  do  the  young  differ  from  the  adults  ?  Place  some 
of  the  young  in  a  jar  with  a  few  fresh  leaves  and  keep 
them  for  a  few  days.  What  happens?  How  do  they 
accomplish  the  change?  Look  in  the  jar  for  cast-off 
skins. 

Examine  the  front  part  of  the  head  of  the  adult 
squash-bug  for  the  mouth.  How  far  back  does  the 
sucking  tube  extend?  How  is  this  used  in  procuring 
food?  Place  a  few  of  the  insects  in  a  fruit  jar  with 
squash  or  pumpkin  stems  or  a  small  piece  of  the 
fruit.  Watch  them  eat.  Describe  the  wings  of  the 


208 


STUDIES  IN  SCIENCE 


insect.  About  what  portion  of  one  overlaps  the  other? 
Look  for  inner  wings.  Is  the  squash-bng  as  great  a 
flier  as  moths  or  butterflies! 


Fig.  41.  The  common  squash-bug  (Anasa  tristis).  a,  Newly 
hatched  nymph;  b,  Second  stage  nymph;  c,  Third  stage  nymph;  d, 
Fourth  stage  nymph;  e,  Fifth  stage  nymph;  f,  Adult;  g,  Egg  mass. 
(All  about  twice  natural  size.) 

Aphids.  Look  on  the  leaves  of  cabbages,  turnips, 
nasturtiums  or  other  plants  for  small  plant  lice  called 
aphids.  Some  lie  flat,  others  resemble  tiny  flies.  Ex- 
amine them  carefully  and  note  the  number  of  stages 
represented.  How  do  the  winged  individuals  differ 


INSECTS  209 

from  the  wingless!  What  kind  of  mouths  have  they? 
To  determine  this,  hold  the  leaf  on  a  level  with  your 
eye  so  that  you  can  see  under  the  insect  and  find  the 
sucking  tube  inserted  in  the  leaf.  Are  there  any  other 
insects  among  the  aphids!  If  so,  what  are  they 
doing  I  (See  Beneficial  Insects,  page  223.)  In  what 
respects  do  aphids  resemble  squash-bugs! 

Discussion.  The  squash-bug  differs  from  moths  and 
butterflies  in  that  it  does  not  have  the  four  complete 
stages  in  its  development.  The  young  when  it  hatches 
from  the  egg  has  the  same  form  as  the  adult  except 
that  it  is  smaller  and  lacks  wings.  As  it  grows  it 
sheds  its  skin  or  molts.  After  the  second  molt,  the 
wings  appear  as  little  flat  pads  on  the  back.  After 
the  last  molt  the  wings  are  fully  developed.  Insects 
that  have  this  kind  of  a  life  history  are  said  to  have 
incomplete  metamorphosis.  The  young  are  called 
nymphs. 

Aphids  have  the  same  kind  of  mouths  as  squash- 
bugs;  that  is,  a  piercing  sucking  tube.  They  also 
have  incomplete  metamorphosis,  but  they  do  not  have 
the  same  kind  of  overlapping  wings.  They  are  among 
the  most  destructive  of  pests.  Few  plants  are  free 
from  them.  They  have  a  life  history  differing  from 
most  other  insects. 

One  of  the  most  destructive  of  these  insects  is  the 
corn-root  aphis,  which  feeds  upon  the  roots  of  corn. 


210  STUDIES  IN  SCIENCE 

Its  life  history  is  similar  to  that  of  all  other  aphids 
except  that  the  eggs  of  all  are  not  cared  for  by  ants. 

The  female  of  the  corn-root  aphis  lays  shiny  black, 
oval  eggs  in  the  ground  during  the  fall  months.  Lit- 
tle brown  ants  find  these,  carry  them  to  their  under- 
ground homes,  and  keep  them  safe  through  the  winter. 
They  often  carry  the  eggs  out  into  the  sunshine  dur- 
ing the  warm  part  of  the  day  and  back  into  the 
burrows  at  night.  These  eggs  hatch  in  the  early 
spring  into  young  aphids.  The  ants  at  once  place 
them  upon  the  roots  of  smart  weeds  or  some  other 
plant.  When  corn  is  beginning  to  grow,  the  ants  place 
the  aphids  on  the  corn  roots,  from  which  they  suck  the 
juices  with  their  sharp  sucking  tubes.  The  ants  get 
their  pay  for  all  this  work  in  the  form  of  honey  dew, 
a  sweet  substance  which  the  aphids  throw  out  of 
their  bodies. 

Each  aphid  that  hatches  from  an  egg  in  the  spring 
is  called  a  stem-mother.  In  less  than  a  month  this 
stem-mother  begins  to  reproduce  young.  All  these 
are  females  which  in  a  month's  time  begin  also  to 
produce  young.  So  in  less  than  two  months  the  stem- 
mother  may  become  the  ancestor  of  thousands  of 
young  lice.  This  goes  on  all  summer. 

Most  of  the  aphids  are  wingless.  Once  in  a  while 
there  is  a  generation  that  has  wings.  These  fly  away 
to  some  other  part  of  the  field  or  to  another  field. 


INSECTS  211 

Some  of  them  drop  to  the  ground,  and  are  found  by 
ants  which  carry  them  at  once  to  the  corn  roots.  In 
the  fall  a  brood  of  males  and  females  is  produced. 
These  females  are  the  ones  that  deposit  eggs  for  the 
new  stem-mothers  next  year.  You  can  readily  see 
why  the  destruction  of  the  ants'  homes  should  be 
encouraged. 

One  of  the  methods  employed  to  destroy  these  pests 
is  to  break  up  the  ground  as  early  as  possible  in  the 
spring,  and  then  before  corn  planting  go  over  it  once 
or  twice  with  a  disc  or  cultivator  in  order  to  destroy 
the  smart  weeds  and  as  many  of  the  ants'  nests  as 
possible. 

Cucumber  beetles.  During  the  fall  you  may  find 
in  the  flowers  of  squash  or  pumpkin  and  on  some  of 
your  flowering  plants  small  cucumber  beetles.  Often 
there  are  two  species;  one  a  dull  green  spotted  with 
black,  the  other  with  black  and  yellow  stripes. 
Determine  if  possible  what  the  beetles  are  doing  in 
the  flowers.  Capture  some  of  them  and  find  out  all 
you  can  about  them.  How  do  they  compare  with 
other  insects  studied  as  to  hardness  of  body?  How 
many  legs  have  they?  How  many  pairs  of  wings? 
How  are  the  outside  wings  placed  in  relation  to  each 
other?  How  do  the  inner  ones  compare  in  length 
•with  the  outer?  What  kind  of  a  mouth  has  the  beetle? 

Discussion.     Cucumber  beetles  are  among  the  worst 


212 


STUDIES  IN  SCIENCE 


garden  pests.  They  are  very  destructive  to  cucum- 
ber plants  as  well  as  to  melons  of  all  kinds.  They  do 
most  of  their  mischief  in  the  larva  stage.  The  adult 
beetles  in  the  fall  are  fond  of  pollen.  That  is  why 
you  find  them  feeding  in  the  flowers.  They  hide  away 
during  the  winter  under  leaves  or  other  rubbish  and 
come  out  about  the  time  the  cucumber  plants  and 
other  cucurbits  are  beginning  their  growth.  They 


Fig.  42.     The    striped    cucumber    beetle     (Diabrolica    vittata).      a, 
Beetle;  b,  Larva;  c,  Pupa.     (Much  enlarged.) 

visit  the  plants  for  two  purposes;  to  feed  upon  the 
young  leaves,  and  to  lay  their  eggs  at  the  lower  part 
of  the  stem.  The  eggs  hatch  into  worm-like  larvae 
that  bore  into  the  stem  and  roots,  often  killing  the 
plant. 

Like   all   beetles   they   have   biting   mouths,    hard 
outer  wings  that  meet  in  a  line  down  the  middle  of 


INSECTS 


213 


the  back,  and  membraneous  inner  wings  that  are 
used  for  flight.  These  wings  are  longer  than  the 
outer  ones  and  when  not  in  use  are  folded  back  under 
the  protective  hard  ones. 


-  -    Q 


THORAX 


Fig.  43.  Parts  of  an  insect:  A,  Antennae;  B,  Compound  eye; 
C,  Mouth;  D,  Palps;  E,  Outer  wing;  F,  Inner  wing;  G,  Ovipositor; 
H,  Foot;  I,  Spiracles  or  breathing  pores. 

While  we  have  chosen  for  study  types  of  insects 
that  are  likely  to  be  found  in  gardens,  you  should 
make  an  effort  to  get  acquainted  with  other  insects 
that  are  found  about  your  home,  school  and  farm. 

Use  the  following  outline  in  keeping  a  record  of 
your  insect  studies.  Keep  any  larvae  that  you  find 
in  glasses  or  boxes,  feed  them  and  watch  their  devel- 
opment. In  most  cases  the  plants  upon  which  you 
find  the  insects  will  determine  what  to  feed  them. 


214  STUDIES  IN  SCIENCE 

, 

INSECT  RECORD 

1.  Name: 

2.  Stage  of  development:     larva,  pupa,  adult,  or,  if  an  insect  with 
incomplete  metamorphosis,  nymph. 

3.  Where  found: 

4.  Characteristics: 

a.  Size — small,  medium,  large,  or  length  in  inches. 

b.  Body  covering — hairs,  spines,  smooth  skin,  etc. 

c.  Color  or  colors. 

d.  Antennae — long,  short,  hair-like,  elbowed,  knobbed,  feath- 
ery, scaly,  etc. 

e.  Eyes — large,  small,  position. 

f.  Legs — number,  special  features. 

g.  Wings — number,  special  features. 

5.  Habits:     movements,  active  in  daylight,  at  night. 

6.  Kind   of  development:      complete   metamorphosis,    incomplete 
metamorphosis. 

7.  Pest,  benefactor  or  neutral. 

8.  If  pest,  how  controlled.    If  benefactor,  what  does  it  do  that  is 
beneficial? 

9.  Remarks.     Any  facts  of  interest  not  noted  above. 

Insects  and  health.  The  house-fly  and  the  mos- 
quito are  of  special  interest  because  they  carry  con- 
tagious diseases  from  one  person  to  another. 

Mosquitoes.  Mosquitoes  breed  in  standing  water. 
You  may  find  the  young,  or  larvae,  in  pools,  ponds, 
rain  barrels  and  tin  cans  that  have  been  thrown  into 
the  rubbish  heap  and  are  partly  filled  with  water 
from  rains.  If  you  find  any  of  the  larvae  (a  common 
name  for  them  is  wrigglers)  place  some  in  glasses 
of  water  and  watch  them.  Determine  how  they  move 
about,  how  they  breathe,  and  how  they  eat.  Tie 
netting  over  some  of  the  tumblers  and  keep  till  the 


INSECTS  215 

insects  change  to  the  adult  mosquitoes.  Place  a  small 
amount  of  kerosene  on  the  surface  of  the  water  in 
one  tumbler  and  note  the  effect. 

The  mosquito  larvae  that  you  find  abundant  in  rain 
barrels,  tin  cans  and  pools  belong  to  the  genus  called 
Culex.  There  are  a  number  of  different  species  of 
these,  some  much  larger  than  others. 

If  you  observed  the  larva  carefully  you  noted  that 
when  at  rest  it  remains  near  the  surface  of  the  water 
with  the  head  end  extending  obliquely  downward. 
At  the  back  part  of  the  body  is  a  small  tube-like  pro- 
jection which  reaches  the  surface  of  the  water.  This 
is  the  breathing  tube,  so,  although  the  insect  lives 
in  water,  it  breathes  the  air  above  the  water.  Around 
the  mouth  the  brushes  of  hair  that  you  see  constantly 
moving  are  making  a  current  of  water  which  brings 
food  to  the  larva.  It  eats  tiny  one-celled  plants  and 
animals  and  bits  of  decaying  matter.  It  remains  in 
the  larval  stage  from  five  to  ten  days  according  to 
the  temperature.  The  warmer  the  weather  the  more 
rapidly  it  grows. 

You  probably  noticed  that  some  of  the  wrigglers 
differ  from  the  larvae.  They  are  darker  and  the  front 
part  of  the  body  is  thick  and  curved.  Each  of  these 
is  a  pupa.  The  pupa  breathes  by  means  of  two  tube- 
like  projections  on  the  back,  so  it  floats  in  the  water 
with  the  head  up  instead  of  down.  It  does  not  eat 


216  STUDIES  IN  SCIENCE 

in  this  stage.  In  from  five  to  seven  days  the  pupa 
skin  splits  open  along  the  back  and  the  mature  mos- 
quito works  its  way  out.  It  floats  a  short  time  upon 
the  empty  skin  while  the  wings  are  drying,  then  it 
flies  away.  By  putting  mosquito  larvae  into  a  jar 
of  water  and  tying  cheese  cloth  over  the  top  you  can 
work  out  the  entire  life  history. 

The  Culex  mosquitoes,  so  far  as  known,  are  not 
dangerous;  that  is,  they  do  not  carry  diseases.  They 
are,  as  everyone  knows,  exceedingly  annoying. 

It  is  only  the  female  that  bites  and  sucks  blood. 
The  male  feeds  upon  the  nectar  of  flowers.  The  hum- 
ming sound  made  by  the  mosquito  is  produced  by  the 
vibrations  of  the  wings. 

The  Anopheles  mosquito  is  more  than  annoying. 
It  transmits  malaria  of  all  kinds;  hence  it  is  often 
called  the  malaria  mosquito.  The  larva  differs  from 
the  Culex  in  that  it  floats  almost  parallel  with  the 
surface  of  the  water  instead  of  obliquely.  The  pupa 
is  very  similar  to  that  of  the  Culex.  The  adults  of 
the  two  kinds  are  somewhat  different.  The  Anopheles 
have  dark  spotted  wings.  The  Culex  when  resting  on 
a  wall  remains  with  the  body  straight;  the  Anopheles 
holds  the  hinder  part  of  the  body  away  from  the  wall 
thus  making  an  angle.  Culex  mosquitoes  are  to  a 
certain  extent  active  during  daylight.  Anopheles  are 
active  only  after  six  o'clock  in  the  evening. 


INSECTS  217 

How  mosquitoes  transmit  malaria.  The  malaria 
germ  is  a  tiny  one-cell  animal  that  passes  through  one 
stage  of  its  life  in  man  and  another  stage  in  the  body 
of  the  mosquito.  In  man  these  germs  live  in  the  red 
blood  corpuscles,  feeding  upon  them.  When  a  germ 
reaches  a  certain  size  in  the  blood  corpuscles  it 
divides  into  a  number  of  distinct  individuals,  which 
float  about  for  a  while  in  the  blood,  then  again  enter 
the  corpuscles  and  go  through  the  same  process  of 
division. 

If  a  malaria  mosquito  sucks  blood  from  an  infected 
person,  a  large  number  of  these  small  germs  called 
spores  are  taken  into  the  stomach  of  the  mosquito. 
Here  they  undergo  certain  changes  and  then  pass 
through  the  wall  of  the  stomach  into  the  body.  They 
finally  reach  the  salivary  glands.  If  now  the  mos- 
quito bites  a  person  who  is  free  from  malaria,  some 
of  these  germs  flow  with  the  saliva  into  the  blood. 
They  enter  the  corpuscles,  feed  and  multiply  and 
cause  chills  and  fever  or  some  other  form  of  malaria. 

So  far  as  is  known  this  is  the  only  way  that  malaria 
is  transmitted;  that  is,  it  can  get  from  one  person  to 
another  only  through  the  agency  of  mosquitoes. 
Sometimes,  however,  the  spores  may  remain  inactive 
or  dormant  for  a  long  period  in  the  blood  of  a  person 
who  has  had  malaria,  then  suddenly  become  active 
and  produce  the  disease. 


218  STUDIES  IN  SCIENCE 

It  is  very  evident  that  all  that  is  necessary  to  eradi- 
cate malaria '  is  to  get  rid  of  malaria  mosquitoes. 
Since  these  insects  breed  only  in  water  it  is  not  a 
difficult  task  in  most  regions  to  exterminate  them. 
Draining  ponds,  covering  pools  that  cannot  be  drained 
with  crude  oil  or  kerosene,  screening  rain  barrels  and 
preventing  the  accumulation  of  tin  cans  or  other  rub- 
bish, will  in  a  short  time  entirely  rid  a  community 
of  these  pests.  The  fact  is,  that  in  many  parts  of  the 
country  they  are  already  kept  well  under  control. 

Where  drainage  is  not  possible  kerosene  may  be 
used  to  kill  the  larvae  and  pupae.  The  oil  spreads 
over  the  surface  of  the  water  making  a  thin  film  on 
top.  The  insects  cannot  penetrate  this  with  their 
breathing  tubes  so  they  are  entirely  shut  off  from  air 
and  soon  die.  This  method  has  been  used  extensively 
in  some  of  the  swampy  regions  of  the  East  and  has 
proved  very  effective. 

Yellow  fever  is  transmitted  from  one  person  to 
another  by  the  yellow  fever  mosquito  in  about  the 
same  manner  that  malaria  is.  The  disease  has  de- 
creased remarkably  during  the  last  ten  years  because 
the  mosquitoes  are  not  allowed  to  breed  as  formerly. 

House-fly.  The  house-fly  is  even  a  greater  menace 
to  health  than  mosquitoes.  Capture  a  house-fly,  put 
it  in  a  glass  or  bottle  and  examine  it.  Describe  its 
eyes,  wings,  legs.  Put  a  bit  of  sugar  or  some  other 


INSECTS 


219 


food  in  the  glass  and  watch  to  see  how  the  fly  eats. 
The  long  projection  that  you  see  is  the  tongue.  This 
is  used  to  lap  up  liquid  food.  When  the  fly  eats  a 
hard  substance  like  sugar  it  first  moistens  it  and  then 
laps  it  up. 

The  life  history  of  the  fly  is  familiar  to  almost 
everyone.  It  has  complete  metamorphosis,  passing 
through  the  four  stages  from  the  egg  to  the  adult 
in  less  than  two  weeks.  Its  chief  breeding  places  are 


Fig.  44.  The  common  house  fly  (Musca  domestica),  showing 
puparum,  adult,  and  larva.  (All  enlarged.) 

stable  manure,  outdoor  closets  and  other  places  where 
there  is  an  accumulation  -of  decaying  vegetable  or 
other  organic  matter. 

The  eggs,  during  the  warm  summer  months,  hatch 
within  twenty-four  hours  after  they  are  laid.  The 
larvae  are  known  as  maggots.  They  are  white  in 
color  and  feed  ravenously  upon  the  food  material  with 
which  they  are  surrounded.  In  from  five  to  seven 


220 


STUDIES  IN  SCIENCE 


days  they  reach  their  full  size  as  larvae;  they  then 
crawl  out  of  the  food  material  into  a  dry  place  where 
they  change  to  pupae.  A  pupa  is  brown  in  color  and 
about  as  large  as  a  grain  of  rice.  The  pupa  stage 
lasts  from  four  to  six  days  in  hot  weather.  In  cool 
weather  it  may  last  ten  or  twelve  days  or  it  may 

remain  in  this  stage 
over  winter.  The  adult 
then  emerges  and  in  a 
few  days  is  ready  to  de- 
posit eggs.  Each  fly 
lays  from  two  hundred 
and  forty  to  four  hun- 
dred eggs. 

For  a  long  time  it  was 
supposed  that  house- 
flies  spend  the  winter 
only  in  the  adult  stage, 
but  recent  experiments 
seem  to  show  that  prob- 
ably most  of  them  pass 
the  winter  in  the  pupa  stage. 

There  is  little  question  that  the  house-fly  is  a  car- 
rier of  typhoid  fever,  dysentery,  cholera  and  tuber- 
culosis. It  carries  the  germs  of  these  diseases  on  its 
sticky  feet  and  on  the  hairs  of  its  body.  When  it 
alights  on  food,  as  it  often  does,  some  of  the  germs 


Fig.  45.  The  dingy 
(Feltia  subgotMca).  a,  Moth 
adult,  with,  wings  expanded;  b, 
Larva,  or  worm,  in  curled-up  posi- 
tion when  feigning  death;  c,  Moth 
with  wings  folded.  (Somewhat  en- 
larged.) 


INSECTS  221 

may  be  dropped  and  afterward  eaten  with  the  food 
and  thus  start  a  disease. 

Flies  may  be  exterminated  from  any  community 
if  all  the  people  work  together.  It  will  be  worth 
while  for  you  to  aid  in  starting  a  fly  campaign  in  your 
district.  There  are  several  things  that  may  be  done. 
First,  it  is  absolutely  necessary  to  get  rid  of  all  the 
breeding  places.  Second,  use  traps  of  various  kinds. 
Place  some  of  them  out-of-doors,  at  some  distance 
from  the  house  near  barns  and  chicken  yards.  By 
using  attractive  bait,  and  by  keeping  other  sources 
of  food  such  as  scraps  and  all  garbage  cans  covered, 
you  can  succeed  in  catching  every  fly  in  the  district. 
Some  of  the  best  baits  are  milk,  banana,  and  bran 
mixed  with  sweetened  water.  Traps  should  be  set 
early  in  the  season  when  the  flies  are  awaking  from 
their  winter  sleep.  In  this  way  they  will  be  prevented 
from  depositing  their  eggs  and  starting  a  new  gen- 
eration. You  may  make  traps  for  yourself  with  little 
cost. 

LIST  OF  COMMON  PESTS 

Garden  pests  not  discussed  above.  Larvae  of  black,  swallow-tail 
butterfly  found  on  parsley  and  parsnips.  Usually  they  may  be  con- 
sidered neutral  since  they  are  not  abundant  enough  to  do  much 
harm.  The  Colorado  potato  beetle.  The  corn  ear- worm  which  feeds 
upon  the  ears  of  sweet  corn,  also  upon  field  corn.  Strawberry  leaf- 
roller.  White  grubs,  which  are  larvae  of  May  beetles  and  feed  upon 
the  roots  of  numerous  garden  plants.  Cut-worms,  which  feed  upon 
stems  of  young  plants,  cabbages,  corn,  etc.,  cutting  them  off  close 


222 


STUDIES  IN  SCIENCE 


to  the  ground.  The  adult  is  a  moth.  Currant  and  gooseberry-worm. 
The  adult  is  a  sawfly. 

Field  pests.  Grasshoppers  feed  upon  grasses,  clovers  and  corn. 
Army- worms  upon  oats,  wheat  and  corn.  Corn-root  aphis.  Corn- 
root  worm.  White  grubs  upon  roots  of  grass  and  corn.  Chinch- 
bugs  upon  wheat,  oats  and  corn.  Hessian-fly  upon  wheat.  Cut- 
worms. Wire  worms,  which  feed  upon  corn.  Cotton-boll  worm  and 
cotton-weevil,  which  feed  upon  cotton. 

Fruit  tree  pests.  Coddling-moth,  canker-worm,  woolly  aphid,  San 
Jose  scale,  scurvy  scale,  apple-tree  borers,  tent  caterpillars,  the 
peach-tree  borer,  plum  curculio,  bark  beetles. 

Enemies  of  forest  or  shade  trees.  Fall  web-worm,  catalpa  sphinx, 
elm  leaf -beetle,  aphids,  leaf  rollers,  bag- worms,  bark  beetles,  scurvy 
scale,  oyster- shell  scale,  San  Jose  scale,  white  marked  Tussock-moth, 
gypsy-moth,  brown  tail  moth,  elm  sawfly,  bronze  birch  borer,  locust 
borer. 

Household  pests.  Cockroaches,  ants,  clothes-moths,  flour-worms, 
mosquitoes,  stable-fly,  house-fly,  carpet-beetles,  corn-meal  moth. 


Fig.  46.  The  celery  caterpilar  (Papilio  Polyxenes).  a,  Larva  from 
side;  b,  Larva  showing  head  with  odoriferous  appendages;  c,  Male 
butterfly;  d,  Outline  of  egg;  e,  Young  larva;  f,  Chrysalis.  (All  about 
natural  size  except  d,  which  is  much  larger.) 

Insects  with  biting  mouths  may  be  controlled  by 
poisons  placed  upon  the  plants  upon  which  they  feed. 


INSECTS  223 

Insects  with  piercing,  sucking  mouths  cannot  be 
destroyed  in  this  way  since  they  feed  from  the  inside 
of  the  leaf  or  stem.  They  may  be  controlled  by  spray- 
ing with  insecticides  that  kill  them  by  coming  in 
contact  with  their  bodies.  Those  most  effective  are 
kerosene  emulsion,  kerosene  and  water,  whale-oil  soap, 
lime-sulphur  mixture,  and  Black  Leaf  No.  40. 

Recipe  for  poison  sprays.  Arsenate  of  lead  is  large- 
ly taking  the  place  of  other  poisons  for  biting  mouthed 
insects.  It  may  be  bought  in  the  form  of  a  paste 
ready  to  dilute.  Directions  for  mixing  are  on  the 
package.  One  pound  of  the  poison  may  be  mixed 
with  about  sixteen  gallons  of  water.  Paris  Green  has 
been  a  favorite  spray  for  biting  insects  for  years. 
The  standard  formula  for  the  mixture  is : 


4  ounces  of  Paris  Green 
V-2  pound  of  lime  slaked 
50  gallons  of  water 
(Many  people  use  it  without  the  lime.) 


Slug  shot  is  a  powder  that  contains  poisonous  mix- 
tures It  is  sifted  upon  the  plants  and  for  small 
gardens  is  quite  effective. 

Lime-sulphur  like  arsenate  of  lead  may  be  bought 
in  packages  ready  to  dilute.  It  is  excellent  for  aphids 
and  scale  insects.  It  is  effective  also  in  destroying 
certain  fungous  diseases  as  blight. 


224  STUDIES  IN  SCIENCE 

BENEFICIAL  INSECTS 

You  must  not  think  that  all  insects  are  pests.  Many 
of  them  are  real  benefactors.  You  already  know 
something  of  the  value  of  bees  in  making  honey  and 
in  carrying  pollen  from  one  flower  to  another.  To 
some  extent  this  is  true  of  moths  and  certain  wasps. 
You  know,  too,  the  value  of  silk  worms  in  producing 
the  silk  of  the  world.  There  are  other  insects  that 
benefit  us  in  quite  a  different  manner,  that  is,  by 
destroying  some  of  the  insect  pests. 

Ladybird  beetles.  Ladybird  beetles  or  ladybugs 
are  among  the  most  beneficial  insects.  Look  on  any 
plants  infested  with  aphids  and  you  will  be  almost 
certain  to  find  ladybugs  both  in  the  adult  and  larva 
stages.  Capture  a  few  of  the  adults  and  place  them 
in  a  glass  with  some  leaves  on  which  are  a  number 
of  aphids.  Watch  to  see  what  they  do.  Examine  a 
ladybird  closely  and  decide  why  it  is  more  correct  to 
call  it  a  beetle  than  a  bug.  What  kind  of  wings 
has  it?  If  you  find  any  of  the  young,  or  larvae, 
place  them  also  in  the  glass  and  feed  them  on  aphids. 
After  a  few  days  they  will  pass  into  the  pupa  stage. 
Note  how  they  fasten  themselves  to  a  leaf  or  a  stem. 
Keep  the  pupa,  and  in  a  week  or  ten  days  the  grown- 
up beetle  will  appear. 

There  are  a  number  of  different  species  of  lady- 


INSECTS  225 

birds  that  are  common  everywhere.  Most  of  them  are 
brightly  colored,  either  red  or  yellow  with  black 
spots.  All  of  them  pass  the  winter  in  the  adult  stage. 
Often  you  will  find  them  congregated  in  great  num- 
bers under  a  shrub  or  hedge  during  the  winter  months. 

Ladybirds  and  their  young  not  only  eat  aphids  but 
eggs  and  larvae  of  potato  beetles  and  many  other 
injurious  insects.  They  aid  more  than  we  can  esti- 
mate in  keeping  pests  in  check.  In  California  they 
are  especially  helpful  in  destroying  scale  insects  that 
feed  upon  orange  and  lemon  trees. 

Braconids  and  Ichneumons.  When  you  studied 
cabbage  worms  perhaps  you  found  that  some  of  them, 
instead  of  pupating,  died  and  had  clinging  to  their 
bodies  a  cluster  of  yellow  cocoons.  Each  of  these 
cocoons  had  in  it  a  small  pupa.  If  you  should  place 
the  pupa  in  a  glass  with  a  cover  over  it,  in  the  course 
of  about  two  weeks  you  would  find  the  glass  full  of 
small  insects  not  larger  than  gnats,  which  had 
emerged  from  the  cocoons.  They  are  the  adult  insects 
and  are  called  braconids. 

If  you  could  go  back  through  the  life  history  of 
this  insect,  this  is  what  you  would  find.  Some  time 
during  the  summer  the  adult  braconids  deposit  their 
eggs  under  the  skin  of  the  cabbage-worm.  Each  egg 
hatches  into  a  small  larva  which  feeds  upon  the  fluids 
in  the  body  of  its  host.  When  it  is  ready  to  change 


226  STUDIES  IN  SCIENCE 

to  a  pupa,  it  breaks  through  the  skin  of  the  worm 
and  spins  its  cocoon  within  which  it  changes  to 
a  pupa.  Usually  the  entire  number  within  the  worm 
come  forth  at  the  same  time  killing  it  instantly. 

The  braconids  destroy  hundreds  of  cabbage  worms 
every  year.  If  you  look  closely  at  one  of  the  adults, 
you  will  see  that  it  has  two  pairs  of  membranous 
wings  and  that  its  body  is  somewhat  wasplike.  In 
fact,  the  braconids  belong  to  the  same  group  of  in- 
sects as  the  bees  and  wasps. 

Sometimes  you  find  tomato-worms  or  grapevine 
sphinx  larvae  almost  covered  with  white  cocoons. 
These  belong  to  another  species  of  braconids  that  live 
in  the  bodies  of  these  insects.  A  tomato-worm  infested 
with  braconids,  while  it  may  not  be  killed  outright 
as  in  the  case  of  the  cabbage-worm,  never  lives  to 
become  an  adult  moth.  In  some  localities  the  braco- 
nids keep  the  tomato-worms  in  check  to  such  a  degree 
that  no  other  remedy  is  needed. 

You  may  find  among  aphids  some  dead  ones  that 
have  hard,  swollen  bodies.  Some  of  them  have  a  small 
round  lid  cut  in  one  side.  These  aphids  have  been 
killed  by  still  another  species  of  braconid.  The  little 
creature  remains  inside  the  aphid  while  it  passes 
through  its  entire  life  history.  When  grown  up  it 
cuts  a  hole  in  the  side  of  the  body  and  comes  forth. 
Braconids  are  called  parasites  because  they  live  and 


INSECTS  227 

feed  in  the  bodies  of  other  insects.  The  insects  in 
which  they  live  are  called  hosts. 

Another  group  of  parasites  is  known  as  ichneumons. 
These  are  somewhat  larger  than  braconids.  Certain 
ichneumons  destroy  hundreds  of  Tussock-moths  wrhich 
are  so  destructive  to  our  shade  trees.  Others  destroy 
tent  caterpillars  that  feed  upon  our  apple  trees,  and 
a  few  destroy  the  gypsy-moth,  which  is  one  of  the 
worst  tree  foes  we  have. 

There  are  a  number  of  other  beneficial  insects  that 
you  will  want  to  get  acquainted  with  as  soon  as  pos- 
sible. Among  them  are:  1.  The  larva  of  the  lace- 
wing  fly,  called  the  aphis-lion  because  it  devours  so 
many  aphids.  2.  Dragon-flies  which  feed  upon  mos- 
quitoes and  gnats.  3.  Tiger-beetles  which  kill  off 
ants  and  some  other  ground  insects.  4.  Several  spe- 
cies of  ground  bettles  that  feed  upon  caterpillars; 
chief  among  these  is  the  beautiful  green  and  blue 
searcher  which  destroys  the  corn-ear  worm.  5.  Many 
of  the  water  beetles  kill  off  great  numbers  of  mos- 
quito larvae.  6.  The  praying  mantis  kills  weevils, 
cottonboll  worm,  and  other  caterpillars. 


CHAPTER  XIV 


FUNGI 

Material.     Mushrooms,  toadstools,  puffballs,  bracket 
fungi,  mold,  smut  and  rust  on  wheat,  oats,  and  corn. 
Fungi  is  the  name  of  a  large  group  of  plants  in- 
cluding mushrooms,  toadstools,  molds  and  many  fung- 
ous growths  found  on  plants  and  animals. 

Mushrooms  or  toad- 
stools. Find  some 
mushrooms  or  toad- 
stools. Where  are 
they  growing!  If 
there  are  a  number, 
look  for  different  sizes 
or  stages  of  develop- 
ment. What  is  the 
condition  as  to  mois- 
ture of  the  soil  or 
other  substance  upon 
which  they  are  found! 
Collect  some  for  indoor  study.  Try  to  get  a  little 
of  the  substance  upon  which  they  are  growing. 
Examine  one  of  the  mushrooms.  How  many  dis- 

228 


Fig.  47.  A  common  mushroom:  A, 
The  mycelium;  B,  The  stem  or  stipe; 
C,  The  pileus;  D,  The  gills  which 
bear  the  spores;  E,  The  young  stage 
of  a  mushroom. 


FUNGI  229 

tinct  parts  has  it?  Look  very  closely  at  the 
soil  to  determine  whether  a  part  of  the  plant  is 
in  this.  (See  Fig.  47  for  the  names  of  the  parts.) 
What  do  you  find  on  the  under  side  of  the  cap  or 
pileus!  The  leaf  like  bodies  are  called  gills.  To 
determine  the  use  of  the  gills  cut  the  stipe  out  close 
to  the  pileus.  Lay  the  pileus,  gills  downward,  on  a 
sheet  of  white  paper.  Place  it  where  it  will  not  be 
disturbed.  After  twenty-four  hours  carefully  lift 
the  pileus.  What  do  you  find  on  the  paper?  The 
powder  is  composed  of  spores.  These  are  the  repro- 
ductive bodies.  They  produce  new  mushroom  plants 
just  as  seeds  produce  corn  or  wheat.  What  is  the 
color  of  the  spores?  What  does  the  print  indicate 
as  to  where  the  spores  are  borne? 

Compare  the  young  stages  of  the  mushrooms  with 
the  older  ones  noting  differences.  If  the  weather  is 
warm,  watch  their  development.  How  rapidly  do  they 
grow?  How  long  do  they  remain  in  good  condition 
after  they  are  fully  grown? 

Look  for  different  kinds  of  mushrooms  and  toad- 
stools. Compare  as  to  shape,  size,  and  color.  Make 
spore  prints  and  note  differences  in  size  and  color  of 
spores. 

Puff  balls.  Where  do  you  find  puffballs  growing? 
How  large  are  they?  Is  the  mycelium  more  or  less 
easily  found  than  that  of  mushrooms?  Cut  one  in 


230  STUDIES  IN  SCIENCE 

two  and  describe  the  inside.  How  does  a  mature  one 
differ  from  a  young  one?  If  you  find  no  mature  ones, 
lay  some  aside  until  they  dry.  Are  there  many  or 
few  spores! 

Discussion.  From  your  observation  you  have  prob- 
ably concluded  that  mushrooms,  toadstools  and  puff- 
balls  are  found  in  places  where  there  is  plenty  of 
moisture  and  some  sort  of  decaying  vegetation.  The 
fact  is  that  these  plants  and  all  other  fungi  are 
dependent  upon  seed  plants  for  their  food.  Since  they 
do  not  have  the  green  coloring  matter  found  in  leaves, 
they  cannot  manufacture  their  own  food.  This  is 
why  you  find  them  growing  among  decaying  leaves, 
stumps  or  logs.  Some  of  them  are  found  in  meadows 
which  are  rich  in  decaying  grasses.  Some  are  found 
in  the  rich,  decaying  matter  around  barns. 

The  thread-like  mycelium  penetrates  the  soil  or 
other  substance  and  procures  the  food.  The  part  that 
is  above  ground  grows  up  for  the  purpose  of  produc- 
ing the  spores.  It  is  called  the  fruiting  body.  The 
spores  of  mushrooms  and  toadstools  are  produced  on 
the  free  edge  of  each  gill ;  those  of  puffballs  are  borne 
inside  the  ball.  The  mycelium  may  grow  for  weeks  or 
months  before  it  sends  up  the  fruiting  body.  During 
dry  or  cold  weather  it  may  remain  alive  but  inactive 
for  months;  then  when  the  proper  conditions  come, 
it  grows  rapidly  and  sends  up  the  spore  bearing  body. 


FUNGI  231 

From  this  you  can  readily  see  that  the  spores  when 
they  germinate  and  grow  produce  the  mycelium. 

Mushrooms  are  of  interest  because  they  furnish 
human  food.  Some  are  edible;  others  are  poisonous. 
The  poisonous  ones  are  frequently  called  toadstools. 
Many  people  raise  edible  mushrooms  for  market  and 
for  canning.  Others  collect  them  for  table  use  from 
the  woods  and  meadows.  These  people  have  learned 
to  recognize  certain  edible  species.  If  you  wish  to 
collect  mushrooms  for  food,  the  best  plan  is  to  take 
a  specimen  to  some  person  in  the  neighborhood  who 
knows  which  ones  are  edible.  There  are  some  gen- 
eral characteristics  that  will  help  you  to  distinguish 
the  edible  from  the  poisonous  kinds. 

1.  Some  of  the  most  deadly  ones  have  the  lower 
part  of  the  stem  surrounded  by  a  cup-like  membrane. 
So  you  should  always  dig  down  far  enough  to  be 
sure  that  no  cup  is  present. 

2.  Avoid  mushrooms  covered  with  scales. 

3.  Poisonous    species    are    likely    to    have    white 
spores;  edible  ones  dark  spores. 

4.  Avoid   those   with   milky   juice   or   with   shiny 
caps. 

5.  Do  not  eat  them  after  the  meat  has  turned  dark. 
All  puffballs  are  edible  although  the  flavor  is  not 

always  as  delicious  as  that  of  most  mushrooms.     All 
the  precaution  that  is  necessary   in   collecting   these 


232  STUDIES  IN  SCIENCE 

for  food  is  to  be  sure  that  they  are  puff  balls  and  not 
young  stages  of  poisonous  mushrooms. 

Bracket  fungi.  Look  on  trees,  stumps  or  logs  for 
bracket  fungi.  What  kind  of  trees  do  you  find  them 
on?  On  what  part  are  they  growing?  Are  the  trees 
alive  or  dead? 

Examine  one  of  the  brackets.  Compare  the  upper 
and  under  surfaces.  Look  for  layers  of  growth.  On 
which  surface  do  they  show  more  distinctly?  Exam- 
ine the  lower  surface  with  a  lens  and  describe  it.  Cut 
a  section  through  the  fungus  and  determine  how 
far  you  can  trace  the  small  tubes.  Cut  off  a  bit  of 
bark  with  some  of  the  younger  specimens  attached 
and  look  for  the  mycelium,  a  mass  of  white  threads  at 
the  base  of  the  fungus.  If  the  tree  is  dead,  slice  off 
a  piece  of  bark  to  determine  whether  or  not  the 
mycelium  penetrates  the  wood. 

Make  a  collection  of  bracket  fungi.  They  may  be 
dried  and  mounted  by  means  of  pins  in  shallow  paste- 
board boxes. 

Discussion.  The  spores  of  bracket  fungi  are  borne 
in  the  tiny  tubes  whose  openings  you  found  on  the 
lower  surface.  The  spores  drop  out,  are  carried  by 
the  wind,  settle  upon  trees,  stumps,  etc.,  where  they 
germinate  and  grow.  The  mycelium  penetrates  the 
wood  feeding  upon  it.  Usually  these  fungi  are  found 
upon  dead  trees,  logs  and  stumps  which  in  time  they, 


FUNGI  233 

with  the  other  fungi,  reduce  to  mere  vegetable  mold 
in  the  soil. 

Some  species,  however,  are  found  feeding  upon  liv- 
ing trees.  Occasionally  they  kill  the  entire  tree;  but 
usually  they  only  injure  some  of  the  branches.  How- 
ever, the  spores  cannot  find  access  to  a  tree  unless 
there  are  wounds  in  the  bark.  If  a  tree  receives  an 
injury  in  any  way,  the  wound  should  be  cared  for  at 
once.  A  coat  of  paint  is  excellent  for  this. 

Mold.  Mold  is  a  fungus  that  is  frequently  found 
in  our  homes.  About  a  week  before  you  are  ready 
to  begin  this  study,  moisten  a  piece  of  stale  bread, 
put  it  on  a  piece  of  pasteboard,  and  turn  a  tumbler 
over  it  to  prevent  it  from  drying.  Keep  it  in  a  warm 
place  but  not  in  a  strong  light,  and  look  at  it  occa- 
sionally. When  there  is  a  good  crop  of  mold,  examine 
it  carefully.  What  color  or  colors  do  you  find?  How 
many  distinct  parts  are  there?  What  do  you  think 
the  threads  are?  The  little  white  or  black  balls? 
To  what  extent  do  the  threads,  or  mycelium,  penetrate 
the  bread?  Put  a  piece  of  white  cloth  over  the  upper 
end  of  your  lead  pencil  and  rub  over  the  black  balls. 
What  happens  ?  What  is  the  black  dust  on  the  cloth  ? 

:'.\     '  '•'  -*  t  • '••  ?!i::-i*    A-  •. ;  '     ;  j  • .  s  •' '  •-*    "tf^  \l~:''..-~~f~.    to    .l":.;-il.  •  ,'-    '•'_-.'..:   •  •""•'?' 

GROWTH  OF  MOLD. 

Experiments.  1.  Moisten  a  piece  of  bread  and  with 
a  small  splinter  or  the  end  of  a  match  transfer  some 


234  STUDIES  IN  SCIENCE 

of  the  dust  or  spores  to  the  bread.  Plant  them  in 
rows.  Turn  a  tumbler  over  the  bread  and  keep  in 
a  warm,  dark  place.  Examine  every  day.  How  soon 
do  you  find  mold  growing  from  the  spores?  How 
long  before  spore  cases,  the  black  balls,  appear? 

2.  Moisten  a  piece  of  bread.     Collect  some  dust 
from  furniture  or  corners  of  the  room.    Place  this  in 
rows  on  the  bread.     Cover  with  a  tumbler  and  watch 
for  results. 

3.  Moisten  two  pieces  of  bread  and  plant  spores 
on  them.    Place  one  in  a  dark,  warm  place;  the  other 
in  a  warm,  sunny  window. 

4.  Get  a  moldy  orange  or  lemon.    What  color  are 
the  spores?    Eub  a  pin  point  over  the  spores  and  then 
insert  the  pin  into  a  good  orange.     Sterilize  another 
pin  by  passing  it  through  a  flame.     Insert  this  in 
another  part  of  the  orange.    Eub  some  of  the  spores 
on  a  small  spot  on  the  skin  of  the  orange.    Place  the 
orange  in  a  covered  jar  or  dish  so  it  will  not  be  dis- 
turbed.   Watch  for  results. 

From  your  experiments  answer  these  questions: 
What  starts  a  growth  of  mold?  What  conditions  aid 
the  growth?  W^hat  may  be  done  to  prevent  mold? 

Make  a  list  of  everything  about  the  home  that  is 
likely  to  be  affected  with  mold.  How  many  different 
kinds  of  mold  have  you  seen,  judging  from  the  color 
of  the  spores? 


FUNGI  235 

Discussion.  Several  different  species  of  mold  may 
be  found  about  your  home.  One  of  the  most  common 
is  bread  mold,  which  has  black  spore  cases  and  is 
sometimes  called  black  mold.  It  produces  a  fluffy 
white  mass  of  mycelium.  Green  mold  is  another 
common  kind.  The  mycelium  is  composed  of  very 
fine  white  threads.  You  saw  some  of  these  around  the 
pin  in  the  orange  before  the  green  spores  appeared. 
Sometimes  you  find  on  fruit  a  very  white  mold  with  a 
compact  mass  of  threads  and  white  spores. 

The  mold  spores  are  so  small  that  one  by  itself 
is  not  visible  to  the  naked  eye.  They  float  about  in 
the  air  and  settle  down  upon  food,  furniture  and 
clothing,  forming  a  part  of  the  dust.  If  they  have 
moisture,  something  to  feed  upon,  and  the  tempera- 
ture is  not  too  cold,  they  grow  rapidly,  producing  first 
the  mycelium  and  then  the  spores. 

The  spores  may  be  killed  by  boiling  water.  You 
found  also  that  they  do  not  thrive  in  strong  sun- 
light. Sterilizing  cans,  bread-jars,  cake-boxes,  etc., 
will  prevent  mold  from  growing. 

Smuts.  Look  at  a  head  of  oats  that  has  smut  on  it. 
Compare  with  a  good  head.  Shake  the  smut-head 
gently  over  a  sheet  of  white  paper.  What  fall  off? 
What  other  parts  of  the  fungus  must  be  present  in 
the  oats!  How  do  you  account  for  the  fact  that  an 
oat  plant  with  smut  is  shorter  and  smaller  in  every 


236  STUDIES  IN  SCIENCE 

way  than  a  healthy  plant?  How  does  the  smut  get 
started  on  the  oats? 

Study  a  head  of  wheat  that  has  smut  on  it  just 
as  you  did  the  oats. 

What  parts  of  corn  are  affected  by  smut?  To  what 
extent  does  it  destroy  an  ear?  Break  up  a  smutted 
ear  and  look  for  mycelium  as  well  as  for  spores. 

Discussion.  A  fungus  like  smut  that  grows  upon 
living  plants  is  called  a  parasite.  All  the  smuts  have 
mycelium  that  penetrate  the  stems  of  the  plants  and 
feed  upon  their  juices.  That  is  why  smutted  plants 
are  always  dwarfed.  The  dust  that  you  find  is,  of 
course,  spores.  These  are  widely  scattered  in  har- 
vesting and  threshing  of  the  grain. 

The  life  history  of  oat-smut  is  interesting.  If  you 
sow  oat  seeds  that  have  smut  spores  on  them,  this  is 
what  happens :  The  spores  germinate  and  grow  soon 
after  the  oat  plant  begins  its  growth.  The  threads  of 
the  mycelium  penetrate  the  young  oat  stem  feeding 
upon  its  sap.  As  the  oat  plant  grows  the  mycelium 
grows  also,  sending  out  many  branches  <ill  through 
the  stem.  When  the  oats  begin  to  head  out,  the 
mycelium  grows  into  all  parts  of  the  head,  and  now  it 
is  ready  to  form  its  spores.  Some  of  the  mycelium 
threads  penetrate  the  glumes  (outer  covering  of  the 
grain),  and  come  to  the  outside  to  form  their  spore 
cases.  Some  form  inside.  Usually  every  grain  or 


FUNGI  237 

what  would  have  been  a  grain  is  filled  with  spores. 

It  is  an  easy  matter  to  prevent  oat-smut.  The  smut 
spores  can  be  killed  before  the  oats  are  planted. 
The  following  recipe  is  used  by  many  farmers:  Put 
one  pint  of  forty  per  cent  formaldehyde,  sold  under 
the  name  formalin,  into  thirty-six  gallons  of  water. 
This  is  sufficient  to  treat  forty  bushels  of  oats.  Put 
the  oats  into  gunny-sacks,  dip  them  into  the  solu- 
tion, leaving  them  from  ten  to  fifteen  minutes.  Then 
spread  out  on  a  floor  to  dry.  Some  farmers  place  the 
oats  on  a  floor  and  sprinkle  them  with  the  solution, 
turning  them  over  with  a  shovel  so  that  every  grain 
is  moistened.  Oat-smut  often  attacks  fifteen  per  cent 
of  the  plants,  which  means  a  loss  of  fifteen  per  cent  of 
the  crop,  often  all  of  the  profit  on  the  crop. 

The  history  of  stinking  smut  on  wheat  is  practically 
the  same  as  that  of  oat-smut  and  it  may  be  prevented 
in  the  same  way. 

Corn-smut  spores  live  over  winter  in  the  soil  of 
the  fields  or  in  piles  of  trash,  especially  stable  manure, 
near  the  fields.  In  the  spring  some  of  them  are  blown 
around,  alighting  upon  the  young  corn  plant.  Here 
they  grow  and  produce  spores  which  blow  to  other 
parts  of  the  plant.  Some  of  these  attack  the  grow- 
ing ears.  To  prevent  corn-smut  care  must  be  taken 
not  to  leave  in  the  fields  material  in  which  the  spores 
can  spend  the  winter.  Another  plan  is  to  go  through 


238  STUDIES  IN  SCIENCE 

the  field,  cut  out  the  affected  stalks,  and  burn  them. 
There  are  a  number  of  other  fungous  diseases. 
Some  of  the  most  familiar  ones  are:  1.  Potato-scab, 
which  may  be  prevented  by  the  same  treatment  as 
oat-smut.  2.  Peach-rot,  which  attacks  the  half-ripe 
peach.  This  may  be  helped  by  burning  all  the  dried- 
up  peaches  that  are  left  on  the  trees  and  all  the  trash 
that  collects  under  the  trees.  3.  Potato-blight,  which 
may  be  prevented  by  spraying  with  Bordeaux  mix- 
ture. 4.  Tomato-blight  should  receive  the  same  treat- 
ment as  that  of  the  potato.  In  both  cases  the  spray- 
ing should  be  done  early,  before  the  blight  has  made 
any  headway. 


CHAPTER  XV 

YEAST  AND  BACTERIA 

Material.  Yeast-cakes  either  dry  or  compressed, 
sugar,  salt,  flour,  several  tumblers  or  wide  mouth 
bottles. 

Experiments.  What  is  yeast?  Examine  a  yeast- 
cake  either  dry  or  compressed.  Of  what  does  it  seem 
to  be  made!  If  you  have  a  dry  cake,  break  off  a 
piece  about  one  inch  square  and  crumble  it  into  2% 
tablespoonsful  of  warm  water  at  about  80°  F.  Do 
not  have  it  too  warm.  Number  six  tumblers,  wide 
mouth  bottles  or  test  tubes. 

(a)  Into  numbers  1,  2  and  3  place  %  teaspoonful 
of  flour  and  Vi  teaspoonful  each  of  sugar  and  salt. 
Mix  them  together  and  stir  in  two  tablespoonsful  of 
warm  water.     Into  this  mixture  stir  one  teaspoonful 
of  the  dissolved  yeast  or  a  email  piece  of  compressed 
yeast. 

(b)  Into  number  4  put  the  same  ingredients  as  in 
1  and  2  but  omit  the  salt. 

(c)  In  number  5  omit  the  sugar.     . . 

(d)  In  number  6  use  nothing  but  water  and  the 
3'east  solution. 

239 


240  STUDIES  IN  SCIENCE 

Place  tumblers  numbered  1,  4,  5  and  6  in  a  warm 
temperature,  between  80  or  90°  F.,  and  allow  them 
to  stand  several  hours  or  over  night. 

Place  number  2  in  a  cool  temperature,  a  refriger- 
ator, or  in  a  pan  of  very  cold  water  and  set  out-of- 
doors. 

Heat  number  3  to  a  high  temperature  by  putting  it 
in  a  pan  of  boiling  water,  or  steaming  in  a  double 
1  toiler  for  half  an  hour. 

After  a  number  of  hours  carefully  compare  the 
different  liquids,  describe  what  you  find  and  state 
any  conclusions  you  may  derive.  How  does  number 
1  differ  from  number  21  From  number  3?  In  which 
has  the  greater  change  taken  place,  in  number  4  or 
5?  Why  do  you  think  number  6  shows  less  change 
than  the  others  which  were  in  the  warm  temperature? 

Make  a  list  of  the  conditions  that  brought  about 
the  most  noticeable  results. 

Making  bread.  Mix  enough  flour  with  the  liquid 
of  number  1  to  make  a  stiff  batter  and  allow  it  to 
stand  in  a  warm  temperature  for  an  hour  or  two. 
What  change  takes  place?  Now  put  in  a  half  cup 
of  warm  water  and  enough  flour  to  make  a  stiff 
dough.  When  thoroughly  kneaded  place  it  in  a  glass. 
Measure  the  height  to  which  it  rises.  Set  in  a  warm 
place  and  in  an  hour  measure  it  again.  How  do  you 
account  for  the  difference?  If  you  wish  to  complete 


YEAST  AND  BACTERIA  241 

the  bread  making  process,  knead  the  dough  again, 
place  it  in  a  patty  pan  and  let  it  rise  once  more. 
Then  bake  it  in  a  hot  oven.  How  do  you  account 
for  the  pores  or  holes  that  you  find  in  the  bread! 

Explanation.  Your  experiments  show  that  there 
is  something  in  the  yeast  cakes  that  is  affected  by 
outside  conditions.  You  found  that  the  liquids  in 
tumblers  numbers  1,  4  and  5  were  cloudy  or  turbid, 
while  in  numbers  2  and  3  the  solid  material  had  set- 
tled to  the  bottom  and  the  liquid  was  clear.  This 
shows  that  something  took  place  in  the  warm  tem- 
perature that  did  not  occur  in  the  very  cold  or  hot 
temperatures. 

Number  6  shows  that  the  materials  put  into  the 
solution  with  the  yeast  influenced  the  changes  that 
took  place. 

While  the  compressed  yeast-cake  looked  like  a 
mass  of  frothy  starch  and  the  dry  one  like  a  mass 
of  corn-meal  and  starch,  each  contained  great  num~ 
bers  of  tiny  plants  known  as  yeast.  A  single  yeast 
plant  is  so  small  that  you  cannot  see  it  without  the 
use  of  a  powerful  microscope.  In  fact,  you  would 
have  to  place  about  2,800  of  them  side  by  side  to  reach 
an  inch  in  length.  One  yeast  plant  is  an  oval,  color- 
less cell.  See  Fig.  48. 

In  a  dry  yeast  cake  there  are  a  great  number  of 
these  tiny  plants  alive  but  not  growing.  They  are 


242 


STUDIES  IN  SCIENCE 


said  to  be  in  a  resting  stage.  In  the  compressed 
yeast  the  small  plants  are  more  active  than  in  the 
dry  yeast.  When  you  place  the  plants  in  the  proper 
conditions  they  at  once  begin  to  grow.  These  condi- 
tions are  moisture,  food,  and  a  warm  temperature  from 
70°  to  90°  F. 

The  food  that  yeast  plants  live  upon  is  some  form 
of  sugar,  fruit  juices  that  contain  sugar,  or  starch 
that  is  converted  into  sugar.  Flour  contains  sugar. 

The  small  yeast 
plant  when  it  begins  to 
grow  multiplies  rapid- 
ly by  a  process  known 
as  budding.  On  the 
side  of  the  cell  a  small 
swelling,  called  a  bud, 
appears.  This  grows 
larger  until  it  is  about 
the  size  of  the  original 
cell  and  similar  in  appearance.  Then  a  second  bud 
appears,  sometimes  on  the  first  cell,  sometimes  on  the 
second,  then  another  and  another  till  there  is  a  chain 
of  cells  making  an  irregular  mass.  Fig.  48. 

As  the  plants  feed  upon  the  sugar  they  change  it 
into  two  new  substances,  alcohol  and  carbon  dioxide, 
C02.  The  bubbles  that  you  found  in  the  liquid  and 
batter  were  C02.  It  is  this  gas  that  collects  in  bub- 


Fig.    48.      Yeast    plants.      A,     A 
single  plant;  B,  A  plant  from  which 
a  bud  is  beginning  to   grow;    C,   A 
chain   of   plants    showing  how   they 
grow  by  budding. 


YEAST  AND  BACTERIA  243 

bles  throughout  the  dough  and  makes  it  swell  or  rise. 
When  you  put  the  bread  into  the  hot  oven  the  C02 
expands  with  the  heat  and  gradually  passes  out  into 
the  air  leaving  the  bread  very  light  and  porous.  The 
alcohol  also  changes  to  vapor  and  passes  into  the  air. 
Number  2  did  not  show  any  growth  of  yeast  because 
the  temperature  was  too  low  for  the  growth  to  take 
place.  Heating  number  3  killed  the  yeast  plants  so 
there  was  no  growth.  Number  6  did  not  grow  because 
of  lack  of  food. 

BACTERIA. 

Material.  Some  fresh  milk;  a  small  piece  of  fresh 
lean  beef;  a  potato;  a  few  small  vials;  several  tumb- 
lers and  wide  mouth  bottles  or  test  tubes;  a  double 
boiler  or  kettle;  a  package  of  sterilized  cotton. 

Experiment.  To  determine  why  milk  sours.  1. 
Place  one  of  the  wide  mouth  bottles  on  its  side  in  a 
kettle  of  warm  water  and  heat  the  water  to  the  boiling- 
point.  With  a  fork  turn  the  bottle  over  and  over 
in  the  water  for  about  ten  minutes.  Take  it  out 
and  stand  it  inverted  on  a  clean  table  until  it  cools. 
Fill  it  half  full  of  fresh  milk,  close  the  top  with  cot- 
ton and  set  it  aside  in  the  schoolroom,  or  in  the 
kitchen  if  the  experiment  is  tried  at  home. 

2.  Into  another  bottle  place  a  small  amount  of 
dust  gathered  from  some  place  about  the  room.  Fill 


244  STUDIES  IN  SCIENCE 

the  bottle  half  full  of  milk  and  stand  it  beside  bottle 
number  1. 

3.  Wash  two  bottles,  fill  each  half  full  of  milk, 
plug  with  cotton,      (a)    Place  one  in  a  warm  tem- 
perature, near  the  stove  or  register,      (b)     Put  the 
other  in  a  very  cool  place.     If  you  have  no  refrig- 
erator, place  it  in  a  pan  of  very  cold  water  and  set 
the  pan  out-of-doors  on  the  north  side  of  the  house. 

4.  Sterilize  a  bottle  as  in  experiment  1.     Fill  it 
half  full  of  fresh  milk  and  stir  into  it  a  half  teaspoon- 
ful  of  very  sour  milk.     Place  it  beside  bottles  num- 
bers 1  and  2. 

5.  Sterilize  a  bottle  as  in  number  1.     Fill  it  half 
full  of  milk  and  set  it  in  a  double  boiler.     Keep  the 
water  boiling  for  about  twenty  minutes.    Remove  the 
bottle  and  cool  it  as  quickly  as  possible.     Plug  with 
cotton  and  place  with  numbers  1  and  2. 

At  the  expiration  of  ten  or  twelve  hours  examine 
the  milk  in  all  the  bottles  to  determine  whether  or 
not  any  changes  have  taken  place.  Examine  again 
after  twenty-four  hours  or  when  definite  changes  have 
occurred.  In  which  bottle  does  the  milk  sour  first? 
In  which  does  it  remain  sweet  longest?  What  is  the 
effect  of  sterilization?  Of  a  warm  temperature?  A 
cool  temperature?  Why  does  milk  sour? 

Keep  bottles  number  2  and  (a)  of  Experiment  3  in 
a  warm  place  for  a  number  of  days.  Does  the  odor  or 


YEAST  AND  BACTERIA  245 

color  indicate  that  anything  besides  souring  is  taking 
place? 

Explanation.  The  souring  of  milk  is  due  to  small 
one-celled  plants  called  bacteria.  If  you  wish  to 
speak  about  one  of  them  you  call  it  a  bacterium. 
They  are  very  much  smaller  than  yeast  plants.  Like 
yeast,  however,  they  grow  and  multiply  very  rapidly 
when  proper  conditions  are  present.  They  multiply 
by  cell  division;  that  is,  one  cell  divides  into  two. 
These  grow  and  in  a  short  time  each  divides  again. 
This  continues  until  in  a  few  hours  there  may  be 
thousands  of  new  cells  from  the  one  individual. 

Your  experiments  have  enabled  you  to  determine 
for  yourself  what  the  proper  conditions  for  growth 
are.  You  found  that  the  milk  in  the  cool  temperature 
kept  sweet  much  longer  than  that  in  the  warm  place. 
Bacteria  grow  and  multiply  rapidly  in  a  warm  tem- 
perature. They  feed  upon  the  sugar  in  the  milk 
changing  it  into  an  acid.  Bacteria  that  sour  milk 
are  not  harmful  to  man.  Sour  milk  is  a  wholesome 
food;  but  usually  we  wish  to  keep  milk  sweet  for 
certain  purposes,  and  for  that  reason  we  keep  it  cool 
to  prevent  the  bacteria  from  growing.  By  using  care 
with  the  utensils  in  which  milk  is  kept  we  may  reduce 
the  number  of  bacteria.  Have  you  thought  out  why 
the  milk  in  bottles  numbers  2  and  4  soured  so  quickly, 
while  that  in  numbers  1  and  5  remained  sweet  so 


246  STUDIES  IN  SCIENCE 

long!  By  keeping  number  1  in  the  boiling  water  you 
killed  all  the  bacteria  that  it  contained,  while  in  num- 
ber 2  you  increased  the  number  of  bacteria  by  put- 
ting in  the  dust.  In  number  4  there  were  a  great 
number  of  bacteria  in  the  sour  milk.  By  heating  the 
milk  in  number  5  you  killed  most  of  the  bacteria. 

Your  experiments  then  lead  to  the  following  con- 
clusions : 

1.  Bacteria  cause  milk  to  sour. 

2.  The  more  bacteria  there  are  present,  the  more 
quickly  milk  sours. 

3.  Sterilizing  the  vessels  in  which  milk  is  kept  aids 
in  keeping  it  sweet. 

4.  A    cool    temperature    retards    the    development 
of  the  bacteria  and  keeps   milk  sweet  longer. 

5.  Heating  milk  for  a  period  of  twenty  or  thirty 
minutes  kills  most  of  the  bacteria  that  it  contains, 
hence  it  remains  sweet  for  a  long  period. 

6.  The  bad  odor  of  the  milk  in  bottles  numbers 
2  and  3  (a)  tells  you  that  there  were  other  bacteria 
in  this  milk  than  those  which  caused  it  to  sour.    They 
caused  the  milk  to  spoil  or  putrefy,  and  milk  in  this 
condition  is  not  only  unwholesome  but  dangerous.    If 
you  heat  milk  for  two  or  three  minutes  you  may  kill 
most  of  the  bacteria  that  cause  sourness,  but  leave 
unharmed  the  ones  that  cause  putrefaction.    The  milk 
in  this  case  may  remain  sweet  for  several  days  and 


YEAST  AND  BACTERIA  247 

yet  be  unwholesome.  To  insure  the  death  of  all  bac- 
teria the  milk  should  be  heated  to  a  temperature 
of  145°  F.  to  167°  F.  and  kept  at  this  temperature 
about  half  an  hour.  This  is  called  pasteurizing  milk. 
Sterilized  milk  is  heated  to  the  boiling  point,  allowed 
to  cool,  then  heated  again  to  the  same  temperature. 
Some  experiments  with  meat. 

1.  Cut  a  piece  of  fresh,  lean  beef  into  small  bits 
and  put  them  into  one  of  the  test  tubes  or  bottles. 
Pour  boiling  water  over  them  and  then  steam  in  a 
double  boiler  for  an  hour.     Plug  the  test  tube  with 
cotton,  cool  as  quickly  as  possible  and  set  aside, 

2.  Put    about    the    same    number    of    pieces    into 
another  bottle.     Pour  cold  water  over  them.     Leave 
the  bottle  open  and  stand  it  beside  number  1. 

3.  (a)  Put  a  piece  of  the  beef  into  another  bottle 
and   place   in   a   refrigerator   or   in   any   cool   place, 
(b)  Put  another  piece  into  a  bottle  and  leave  in  a 
warm  temperature. 

Look  at  all  of  the  bottles  every  day  noting  the 
changes  that  take  place.  Which  first  shows  evidence 
of  spoiling!  Which  keeps  in  a  good  condition  long- 
est? What  conclusions  do  you  come  to  as  to  why 
meat  spoils! 

Explanation.  From  your  study  of  milk  you  have 
probably  concluded  the  beef  spoils  because  of  bac- 
teria. Boiling  kills  the  bacteria;  thus  the  beef  in 


248  STUDIES  IN  SCIENCE 

bottle  number  1  kept  in  a  good  condition  longer  than 
that  in  number  2.  The  piece  of  beef  that  was  placed 
in  number  3  (b)  without  moisture  kept  fresh  longer 
than  number  2  because  bacteria  must  have  moisture 
in  order  to  grow  and  develop.  While  there  is  some 
moisture  in  the  meat  itself  the  greater  amount  in 
number  2  made  rapid  growth  possible.  Number  3 
(a)  simply  shows  that  the  bacteria  develop  more 
slowly  in  a  cool  temperature. 

Some  experiments  with  potatoes.  Wash  a  potato 
and  boil  until  it  is  cooked  through.  Sterilize  a  knife 
by  holding  it  in  a  flame  or  boiling  water  a  few  minutes, 
(a)  Cool  the  potato,  then  cut  off  a  slice  about  half 
an  inch  thick,  place  on  a  saucer,  turn  a  tumbler  over 
it,  and  place  in  a  dark  part  of  the  room,  (b)  Cut 
another  slice  and  over  this  scatter  a  little  dust  col- 
lected from  the  room.  Cover  this  also  with  a  tumbler 
and  place  beside  the  first  specimen,  (c)  Cut  another 
slice  and  let  some  one  who  has  dirty  fingers  press 
them  into  .the  potato;  treat  as  in  (a)  and  (b).  (d) 
Prepare  another  slice  exactly  like  (b),  but  after  cover- 
ing with  the  tumbler  set  in  a  sunny  window,  (e)  On 
another  slice  put  some  dust  as  in  (b),  then  sprinkle 
with  water  in  which  you  have  put  a  few  drops  of 
formalin.  Set  beside  (b). 

Look  at  the  specimens  every  day  keeping  a  record 
of  what  happens. 


YEAST  AND  BACTERIA  249 

Explanation.  You  may  find  several  different  things 
taking  place  on  the  potatoes.  Some  may  have  bright 
red  or  yellow  spots.  These  are  masses  of  certain  kinds 
of  bacteria  that  are  growing  and  feeding  upon  the 
potato.  You  may  find  that  on  some  a  growth  of  mold 
has  started.  The  greater  and  more  rapid  growth  on 
the  potato  of  experiments  (b)  and  (c)  shows  that  dust 
contains  bacteria.  The  failure  of  the  bacteria  to  grow 
on  the  potato  in  the  window  and  on  the  one  with  for- 
malin proves  that  sunlight  is  a  real  enemy  of  bacteria 
and  that  formalin  kills  them. 

From  your  experiments  and  the  explanation  you 
have  learned  something  about  a  few  of  the  bacteria 
that  are  found  around  your  home  and  school.  There 
are,  however,  many  other  kinds  that  you  will  learn 
more  about  in  high  school  and  college.  Just  how  many 
different  species  of  bacteria  there  are  nobody  knows, 
but  we  do  know  that  these  little  organisms  are  abund- 
ant everywhere.  They  are  in  the  air,  the  water,  the 
soil,  in  the  dust  that  settles  upon  furniture  and  other 
objects  in  the  home,  and  in  certain  kinds  of  food, 
notably  butter,  cheese  and  vinegar. 

Most  bacteria  are  perfectly  harmless;  some  are  real 
friends.  Among  the  most  beneficial  are  those  that 
work  in  soil  changing  into  soluble  form  the  compounds 
found  there  both  in  the  broken -up  rock  and  in  the 
humus  so  that  they  may  be  dissolved  in  the  water 


250 


STUDIES  IN  SCIENCE 


and  taken  .into  the  root  hairs.  Other  kinds  of  bac- 
teria that  we  must  consider  our  friends  are  those 
that  cause  decay  of  all  kinds  of  dead  plants  and 
animals. 

Bacteria  are  of  three  different  forms:  1.  Cocci, 
which  are  spherical;  2.  Bacilli,  which  are  rod-like  in 
shape;  3.  Spirilla,  which  are  in  the  form  of  a  spiral. 

Bacteria  and  health. 
Some  bacteria  are  dead- 
ly enemies  because  they 
cause  some  of  cur 
most  dangerous  d  i  s  - 
eases,  chief  among 
which  are  tuberculosis, 
typhoid,  diphtheria, 
dysentery,  pneumonia, 
grippe,  and  colds. 

We  often  speak  of 
bacteria  that  cause  these 
diseases  as  germs.  When  these  germs  are  taken  into 
the  human  body  they  may  in  a  short  time  begin  to  grow 
and  multiply.  In  the  process  of  growth  they  produce 
poisons  known  as  toxins.  It  is  these  poisons  that  cause 
fever  and  sickness.  An  important  point  to  remember 
is  that  none  of  these  diseases  start  unless  the  germs 
are  in  some  way  transmitted  from  a  person  who  is  ill 
to  one  who  is  well.  If  people  who  have  these  diseases 


Sx 


Fig.  49.  A  group  of  various  kinds 
of  bacteria.  A,  Coccus  forms:  B, 
Spirillum  forms ;  C,  Bacillus  forms. 


YEAST  AND  BACTERIA  251 

were  careful  not  to  allow  any  of  the  germs  to  be  car- 
ried from  the  sick  room  and  distributed  to  other  people, 
all  infectious  and  contagious  diseases  could  within  a 
few  years  be  exterminated. 

Quarantine  and  disinfectants  are  means  taken  to 
prevent  the  spread  of  diseases.  As  soon  as  the  health 
officer  in  any  community  knows  of  a  case  of  a  contag- 
ious or  infectious  disease,  and  it  should  be  reported  to 
him  by  the  physician  as  soon  as  discovered,  he  at  once 
puts  up  a  placard  with  the  name  of  the  disease.  This 
is  the  signal  for  everyone  except  the  nurse  and  physi- 
cian to  stay  out.  People  who  are  quarantined  should 
realize  that  while  it  is  a  misfortune  it  is  no  disgrace. 
They  should  do  everything  in  their  power  to  keep 
the  quarantine. 

Disinfectants  are  substances  that  are  used  to  kill 
bacteria  that  may  escape  from  the  sick  room  and  infect 
other  people.  Carbolic  acid  is  one.  This  should  be 
made  into  a  weak  solution,  which  means  about  three 
and  one-half  ounces  of  carbolic  acid  to  a  gallon  of 
water,  or  four  teaspoonfuls  to  a  pint.  Clothes  and 
vessels  used  in  a  sick  room  should  be  washed  with 
this  solution.  The  burning  of  sulphur  candles  in  a 
room  is  a  fairly  good  disinfectant  for  most  disease 
germs.  Of  course,  sulphur  must  be  burned  when  there 
is  no  one  in  the  room,  since  human  beings  are  poisoned 
by  the  fumes.  Formaldehyde  is  now  used  most 


252  STUDIES  IN  SCIENCE 

commonly  in  disinfecting  buildings  or  rooms.  Special 
directions  are  necessary  if  this  work  is  done  properly. 
In  many  places  school  buildings  are  disinfected  at 
least  once  a  month.  Can  you  explain  why? 

Besides  the  use  of  disinfectants  there  are  other  ways 
to  prevent  the  spread  of  disease  bacteria.  One  is 
cleanliness;  keeping  the  air  we  breathe  and  the  food 
we  eat  free  from  disease  germs.  This  means  care  in 
the  home  and  school.  It  means  as  little  dust  as  pos- 
sible, the  use  of  vacuum  cleaners,  of  dustless  dusters, 
of  rugs  instead  of  carpets;  in  fact,  everything  that 
keeps  dust  out  of  the  air.  Water  heated  to  the  boiling 
point  kills  many  germs.  This  should  be  used  freely 
in  washing  dishes  and  clothing. 

One  of  your  experiments  suggests  another  method 
of  combating  bacteria,  that  is  by  sunlight.  Few  kinds 
of  bacteria  can  live  in  the  light  of  the  sun.  Clothing 
and  bedding  should  be  exposed  to  the  sun  and  air 
occasionally  to  kill  any  germs  that  may  be  hiding  in 
them,  and  to  keep  them  in  a  sanitary  condition. 

Fighting  bacteria  with  good  health.  After  all,  one 
of  the  strongest  weapons  with  which  to  combat  dis- 
ease germs  is  good  health  and  germ  resisting  power. 
When  germs  are  taken  into  the  body  the  white  cor- 
puscles of  the  blood  at  once  begin  to  destroy  them. 
If  the  corpuscles  are  numerous  and  the  blood  in  good 
condition,  the  corpuscles  are  likely  to  come  off  victor- 


YEAST  AND  BACTERIA  253 

ions  in  their  struggle  with  the  germs.  The  corpuscles 
are  aided  in  this  work  by  another  substance  in  the 
blood  known  as  the  germicidal  substance.  This  attacks 
the  germs  killing  them  before  they  can  produce  enough 
toxin  to  cause  sickness.  The  blood  also  produces  an 
anti-toxin  which  helps  to  destroy  the  toxin.  Now  if 
your  body  is  in  a  healthy  condition  all  of  these  agents 
work  together  and  the  result  is  that  the  bacteria  are 
destroyed  without  your  having  any  evidence  of  their 
presence  in  your  body,  or,  if  they  succeed  in  causing 
illness,  the  attack  is  likely  to  be  a  mild  one. 

Certain  diseases  are  treated  by  putting  into  the 
blood  some  of  the  anti-toxin  of  the  disease  so  the  blood 
will  set  about  making  more  of  the  germicidal  sub- 
stance and  thus  always  have  enough  to  prevent  the 
disease  from  getting  a  hold  in  the  body.  Typhoid 
fever,  diphtheria  and  smallpox  are  satisfactorily 
treated  in  this  manner. 

People  are  not  likely  to  take  certain  diseases  such 
as  smallpox  and  measles  a  second  time.  This  is  because 
the  disease  leaves  enough  of  the  germicidal  substance 
in  the  blood  to  kill  off  any  germs  of  the  disease  that 
may  attack  the  body  later. 

Here  are  some  simple  rules  to  follow  in  combating 
bacteria  that  cause  human  diseases: 

1.  Keep  all  rooms,  especially  sleeping  rooms,  wel] 
ventilated. 


254  STUDIES  IN  SCIENCE 

2.  Keep  window  shades  up  to  allow  the  sunlight 
to  enter  rooms  freely. 

3.  Avoid   stirring  up  dust  in  living  rooms,   and 
remove  with  an  oiled  or  damp  cloth  any  dust  that 
settles  upon  furniture  and  other  objects. 

4.  Keep  the  body  clean  and  pay  particular  atten- 
tion to  the  hands  and  nails. 

5.  Do  not  form  the  habit  of  spitting  in  the  street, 
but  help  all  you  can  to  enforce  ordinances  against 
spitting  in  public  places. 

6.  Do  not  eat  fruit  that  has  been  exposed  to  the 
dust  of  the  street  without  washing  thoroughly. 

7.  In  case  of  a  typhoid  fever  epidemic  boil  drink- 
ing water. 

8.  Keep  up  a  constant  warfare  against  flies  and 
mosquitoes    till    they    are    exterminated    from    your 
community. 

9.  Keep  your  body  in  good  health  by  following 
the  proper  rules  of  eating,  exercising,  sleeping,  and 
avoiding  stimulants  such  as  tobacco  and  alcohol. 

10.  When  you  sneeze  or  cough  be  sure  to  cover 
your  nose  and  mouth  with  your  handkerchief.     This 
precaution  will  keep  your  disease  germs  from  spread- 
ing to  other  people. 


CHAPTER  XVI 

PROPAGATING  PLANTS  BY  CUTTINGS 

Material.  Geraniums,  coleus,  lantana,  wandering 
Jew,  heliotrope,  or  any  other  plants  that  may  be 
started  from  cuttings  or  slips;  a  sharp  knife;  a  pro- 
pagating  box  and  flower  pots. 

While  many  of  our  garden  plants,  both  flowers  and 
vegetables,  are  grown  from  seeds,  some  are  propa- 
gated in  other  ways.  Some  familiar  examples  are 
the  growing  of  onions  from  bulbs,  of  potatoes  from 
tubers,  of  strawberries  from  runners.  Make  a  list 
of  all  the  different  methods  of  propagating  plants 
that  you  know  with  an  example  of  each. 

The  propagating  box.  One  of  the  first  things  to  do 
if  you  are  planning  to  make  cuttings  is  to  prepare 
a  box  in  which  to  grow  them.  Any  wooden  box  will 
serve.  If  you  grow  them  in  the  schoolroom  or 
at  home,  you  will  have  better  success  if  you  make 
one  side  of  the  box  about  two  inches  lower  than  the 
other  so  that  it  will  have  a  sloping  top.  Nail  a  nar- 
row strip  of  wood  just  inside  the  box  all  the  way 
around  so  you  may  place  a  pane  of  glass  over  it. 
Fill  the  box  about  two-thirds  full  of  clean  sand  or 

255 


256  STUDIES  IN  SCIENCE 

other  soil,  moisten  thoroughly,  and  the  box  is  ready 
for  the  cuttings. 

You  may  make  a  box  that  will  serve  as  a  window- 
box  as  well  as  for  propagation.  This  should  be  made 
the  right  length  to  fit  the  window  in  which  you  wish 
to  place  it.  It  should  be  about  eight  inches  deep 
and  from  six  to  eight  inches  wide.  Any  kind  of 
lumber  will  serve,  but  cypress  is  the  best  since  it 
stands  moisture  better  than  other  woods.  Bore  two 
or  three  holes  in  the  bottom  for  drainage  and  put 
in  first  a  layer  of  coarse  material,  cinders  or  pebbles, 
then  put  in  the  soil.  If  the  soil  is  rich,  heavy,  black 
loam,  a  small  amount  of  sand  mixed  with  it  will  be 
an  advantage.  If  it  is  not  very  rich,  humus,  either 
leaf  mold  or  well  rotted  stable  manure,  will  improve 
it.  A  good  soil  mixture  for  potting  or  for  window- 
boxes  is  one-half  loam,  one-fourth  sand  and  one- 
fourth  humus. 

SOFT  WOOD  CUTTINGS 

Cuttings.  A  common  method  employed  in  growing 
certain  plants  is  by  the  use  of  cuttings.  You  may  use 
different  parts  of  plants  to  make  cuttings.  Some 
begonias  are  propagated  by  leaf  cuttings.  You  make 
tuber  cuttings  when  you  plant  potatoes.  Most  cut- 
tings, however,  are  made  from  stems. 

There  are  two  kinds  of  stem  cuttings,  the  soft  or 


PROPAGATING  PLANTS  BY  CUTTINGS 


257 


green  wood,  and  the  hardwood.  A  number  of  plants 
grown  in  the  garden  and  in  the  home  are  propagated 
by  softwood  cuttings.  Some  of  the  best  ones  to  use 
for  this  purpose  are  coleus,  sometimes  called  foliage 
plants,  salvia,  geraniums,  lantana,  balsam,  heliotrope, 
tradescantia  or  wandering  Jew. 

Choose  a  fresh,  thrifty  looking  branch  of  coleus 
or  other  plant  for  your  cutting.     Look  at  it  a  mo 


Fig.  50.     a,  Where  the  cut  is  made;   b,  How  the  cutting  should  look 

when  finished. 

ment  to  determine  how  the  leaves  are  arranged. 
We  call  the  place  on  the  stem  from  which  the  leaves 
grow  a  node.  Use  a  sharp  knife  and  make  a  clean 
horizontal  cut  just  below  a  node.  (Fig.  50a  shows  how 
this  is  done.) 

Cut  off  the  lower  leaves  and  trim  the  ends  from 
the  upper  ones.  Why  is  this  done  I  You  know  that 
leaves  of  plants  constantly  give  out  moisture.  By 


258  STUDIES  IN  SCIENCE 

thus  reducing  the  leaf  surface  the  cutting  will  not 
lose  so  much  moisture.  Fig.  50b  shows  how  the  cut- 
ting should  look  when  finished. 

With  a  wooden  paddle  or  sharpened  stick  make  a 
drill  in  the  sand  or  soil  of  your  propagation  box. 
Place  the  cuttings  in  the  drill  about  two  inches  apart. 
With  your  fingers  firm  the  moist  soil  closely  around 
them.  Water  the  plants  thoroughly  and  keep  in  a 
dim  light  for  two  or  three  days.  You  may  accom- 
plish this  by  covering  the  box  with  a  newspaper. 
After  two  or  three  days  give  the  plants  plenty  of 
light  and  water  when  needed.  They  should  from  the 
beginning  be  kept  in  a  warm  temperature.  They  need 
air  as  well  as  light  and  water,  so  if  you  are  growing 
them  in  a  glass  covered  box  be  sure  to  raise  the 
cover  a  few  minutes  every  day  for  the  purpose  of 
ventilation. 

There  is  another  way  in  which  cuttings  may  be 
grown  that  is  very  satisfactory  for  either  school  or 
home.  Place  the  usual  pebbles  or  coarse  materials 
for  drainage  in  the  bottom  of  a  large  flower  pot  eight 
or  ten  inches  in  diameter,  and  fill  with  soil  leaving 
a  space  in  the  middle.  Plug  up  the  hole  of  a  small 
pot  three  or  four  inches  in  diameter  and  set  this 
inside  the  large  one.  Fill  the  space  between  pots 
with  soil  and  place  the  cuttings  here.  Keep  the  small 
pot  filled  with  water.  Coleus  plants  may  not  only  be 


PROPAGATING  PLANTS  BY  CUTTINGS  259 

started  in  this  way  but  they  may  be  kept  all  winter 
making  a  very  pretty  mass  of  foliage. 

The  callus  and  roots.  What  do  you  expect  your 
cuttings  to  do  in  the  propagation  box?  The  very  best 
way  to  answer  this  is  to  wait  three  or  four  weeks 
until  the  cuttings  are  ready  to  be  transplanted.  Then 
take  one  up  and  examine  the  cut  surface.  What  has 
taken  place!  The  rounded  portion  at  the  end  of  the 
stem  where  the  cut  has  healed  is  called  a  callus.  The 
first  thing  the  cutting  does  is  to  form  a  callus  by  lay- 
ing down  a  new  layer  of  cells  over  the  cut  surface. 
After  this  it  sends  out  roots.  If  a  callus  does  not 
form  the  cutting  dies.  Where  have  the  roots  ap- 
peared! Compare  different  cuttings  to  determine 
whether  they  sent  out  their  roots  with  equal  rapidity. 

Transplanting.  Now  that  the  roots  have  developed 
your  cutting  is  ready  to  transplant.  You  may  trans- 
plant it  into  a  window-box  or  flower  pot.  If  you  have 
no  pots,  tin  cans  will  serve  equally  well.  Punch  a  few 
holes  in  the  bottom  for  drainage.  Place  a  few  peb- 
bles or  bits  of  broken  pottery  in  the  bottom  of  the 
pot  or  can.  Then  fill  it  half  full  of  soil  using  the 
mixture  suggested  above.  Place  the  cutting  in  the 
center  taking  care  to  spread  out  the  roots.  Hold  it  in 
place  with  your  left  hand  while  with  your  right  hand 
you  fill  the  space  around  it  with  soil,  firming  it 
closely  about  the  plant.  Do  not  fill  the  pot  to  the 


260  STUDIES  IN  SCIENCE 

brim.  Leave  a  space  of  at  least  three-fourths  of  an 
inch.  Water  thoroughly  and  leave  in  a  dim  light 
for  two  or  three  days. 

Caring  for  the  plants.  After  the  plants  are  well 
started,  place  them  in  a  warm,  well-lighted  window; 
a  south  window  is  best  but  they  will  do  fairly  well 
with  care  in  other  windows. 

The  chief  points  to  consider  in  caring  for  your 
plants  are:  First,  to  see  that  they  have  the  right 
amount  of  water.  It  is  better  to  give  them  a  thorough 
drenching  two  or  three  times  a  week  rather  than  a 
little  sprinkle  every  day.  When  the  soil  looks  dry 
on  top  it  is  time  to  water.  The  temperature  of  the 
water  should  not  be  lower  than  that  of  the  room  in 
which  the  plants  are  kept.  Besides  water  plants  need 
fresh  air.  This  is  easily  supplied.  Air  that  is  fresh 
enough  for  you  to  thrive  in  is  all  right  for  your 
plants.  You  should  be  careful,  however,  when  the 
weather  is  severe  not  to  allow  cold  air  from  an  open 
door  or  window  to  strike  them'.  During  the  very 
cold  weather  ventilate  from  another  room. 

Plants  also  need  certain  mineral  foods  that  are 
obtained  from  the  soil.  If  soil  is  well  supplied  with 
humus,  it  is  probably  rich  enough.  If  not,  a  fertilizer 
may  be  used.  The  following  recipe  is  recommended 
by  gardeners:  Procure  three  ounces  of  nitrate  of 
soda,  one  ounce  phosphate  of  soda,  and  two  ounces 


PROPAGATING  PLANTS  BY  CUTTINGS  261 

of  sulphur  of  potash.  Pulverize  and  mix  these  mate- 
rials thoroughly.  When  required  for  use  put  a  level 
tablespoonful  into  a  gallon  of  hot  water.  When  cold 
use  about  a  teacup  full  for  pots  five  and  six  inches 
in  diameter  and  more  or  less  in  proportion  to  the 
size  of  the  pots.  Do  not  apply  oftener  than  once  in 
two  weeks.  Be  careful  not  to  allow  the  nitrate  to 
touch  the  foliage. 

Value  of  cuttings.  Why  is  it  an  advantage  to 
propagate  plants  by  cuttings  instead  of  seeds?  One 
advantage  is  that  you  get  results  much  sooner.  The 
most  important  advantage,  however,  is  that  when 
you  use  a  cutting  you  are  perfectly  sure  to  get  the 
particular  variety  of  plant  from  which  the  cutting 
is  made.  You  cannot  always  be  certain  of  the  exact 
variety  when  seeds  are  used.  In  many  cases  seeds  do 
not  hold  true  to  variety. 

Softwood  cuttings  may  be  made  at  any  season. 
House  plants  that  have  done  well  over  winter  may  be 
used  to  make  cuttings  in  the  early  spring  to  trans- 
plant later  to  the  yard  or  garden.  Late  summer  is 
a  good  time  to  make  cuttings  for  winter  blooming. 

HARD  WOOD  CUTTINGS 

Material.  Twigs  or  small  branches  from  grape- 
vines and  shrubs  of  various  kinds. 


262  STUDIES  IN  SCIENCE 

Hardwood  cuttings  of  shrubs  or  trees  must  be  made 
late  in  the  fall  or  winter  when  the  plants  have  stopped 
their  work  and  are  inactive.  They  are  sometimes 
called  dormant  cuttings  because  they  are  made  when 
the  plants  are  in  a  dormant  or  resting  condition. 

You  may  propagate  grapes,  currants  and  goose- 
berries, as  well  as  almost  all  of  our  ornamental  shrubs, 
by  means  of  cuttings. 

Grape  cuttings.  If  you  have  access  to  a  grape- 
vine, go  out  and  examine  it.  Find  the  stems  that 
have  grown  this  season.  How  long  are  they?  Take 
some  actual  measurements.  How  do  they  differ  from 
the  older  portions  of  the  stem?  Find  where  the  leaves 
were  attached.  Where  are  the  tendrils  in  relation  to 
the  leaf  scars'?  Do  grapevines  depend  wholly  upon 
tendrils  for  climbing?  Describe  the  buds.  Are  they 
opposite  or  alternate  in  arrangement?  Where  is  the 
bud  situated  with  reference  to  the  leaf  scar? 

Make  the  grape  cutting  from  this  season's  growth. 
Use  care  in  making  the  cut.  Place  your  knife  on  the 
side  of  the  stem  opposite  a  bud  and  on  a  level  with 
the  top  of  it.  Now  make  a  slanting  cut  downward 
so  that  the  knife  will  come  out  just  below  the  bud. 
You  have  thus  made  an  oblique  cut  directly  through 
a  node.  Each  cutting  should  have  at  least  three 
good  buds.  When  you  have  made  a  number,  tie  them 
together  into  a  bundle.  Nurserymen  tie  them  in 


PROPAGATING  PLANTS  BY  CUTTINGS  263 

fifties  and  hundreds.  Place  them  in  a  box  of  moist 
sand  or  soil  taking  care  that  the  lower  end  is  well 
covered  with  sand.  Put  the  box  in  a  cellar  or  other 
cool  place.  It  may  be  set  out-of-doors  ,  and  covered 
with  straw  or  sand.  If  the  box  is  kept  in  the  cellar, 
look  at  it  occasionally  during  the  winter  to  see  that 
the  sand  does  not  dry  out. 

Shrub  cuttings.  If  you  should  like  to  have  shrubs 
on  your  home  or  school  grounds  and  are  willing  to 
wait  a  year  or  two,  you  can  easily  start  them  by  the 
use  of  cuttings.  The  following  are  easily  propagated 
in  this  way  and  are  excellent  shrubs  for  the  home 
grounds:  Japanese  barberry,  common  barberry,  all 
the  bush  honeysuckles,  snowballs,  high  bush  cran- 
berry, hydrangeas,  snowberry,  and  all  the  spireas. 

Frequently  in  parks  and  home  grounds  these  shrubs 
are  pruned  during  the  early  winter.  Ask  the  owner 
for  some  of  the  fresh  branches  and  use  them  to  make 
cuttings.  If  no  pruning  is  in  progress,  ask  some  one 
who  owns  large  shrubs  to  let  you  have  a  few  young 
branches.  They  may  be  taken  from  the  thickest  parts 
without  being  missed.  Use  the  same  plan  that  is 
suggested  for  grape  cuttings.  You  will  find  that  some 
of  the  shrubs  have  many  nodes  and  therefore  the 
buds  are  very  close  together,  so  in  order  to  have  your 
cutting  six  or  eight  inches  long  it  may  have  a  large 
number  of  buds.  In  that  case  it  is  a  good  thing  to 


264  STUDIES  IN  SCIENCE 

cut  off  the  lower  buds  leaving  two  or  three  at  the 
top.  Tie  the  shrub  cuttings  together  and  place  them 
as  you  did  the  grape  cuttings  in  a  cool,  moist  place 
for  the  winter. 

What  do  you  expect  your  cuttings  to  do  during 
the  winter?  You  must  wait  until  spring  to  be  sure 
of  the  answer.  Then  if  you  look  at  your  cuttings, 
you  will  find  that  they  have  made  a  callus  around 
the  margin  of  the  cut.  Probably  some  of  them  will 
have  already  sent  out  roots. 

Setting  out  the  cuttings.  Just  as  soon  as  the 
ground  in  your  garden  can  be  worked  in  the  spring 
set  out  your  cuttings.  Dig  a  trench  deep  enough 
so  that  when  the  cuttings  are  placed  in  it  only  the 
topmost  bud  of  each  will  stand  above  the  surface  of 
the  soil.  Place  them  from  eight  to  nine  inches  apart 
and  firm  the  soil  well  around  them.  During  the 
summer  they  should  be  kept  free  from  weeds  and 
cultivated  carefully.  If  the  season  is  a  very  dry  one 
and  they  begin  to  show  signs  of  wilting,  they  should 
be  watered. 

The  second  spring  or  fall  they  will  be  ready  to 
transplant  to  their  permanent  places  on  your  home 
ground. 


CHAPTER  XVII 


FRUIT  AND  FRUIT  TREES 

Material.  Fruit  trees  of  the  neighborhood;  twigs 
of  apple  and  other  trees;  fruit  of  apple,  pear,  orange 
and  others. 

Study.  Make  a  list  of  fruit  trees  that  grow  in  your 
community.  For 
what  purpose  are 
they  grown!  Which 
species  is  most  abun- 
dant! Which  next! 
What  fruits  are  on 
the  market  that  do 
not  grow  in  your 
neighborhood!  What 
fruit  trees  do  you 
consider  most  impor- 
tant the  world  over! 

The  apple.  Examine  an  apple.  What  parts  do  you 
find!  What  is  the  use  of  the  skin!  To  answer  this 
remove  the  skin  from  an  apple  and  then  allow  the 
apple  to  stand  on  the  table  for  several  days.  Why 
is  a  thick  skin  of  value  when  apples  are  to  be  shipped 

265 


Fig.  51.  Section  of  an  apple  flower: 
a,  Beceptacle;  b,  One  of  the  sepals;  c, 
One  petal;  d,  Stamens;  f,  Upper  part 
of  pistil;  e,  Ovary,  the  lower  part  of 
the  pistil. 


266 


STUDIES  IN  SCIENCE 


or  kept  a  long  time?  Compare  the  skin  of  early  and 
late  apples.  Notice  the  shape  of  the  apple  where  the 
stem  is  attached.  The  hollow  space  around  the  stem 
is  called  the  cavity.  Examine  the  opposite  end  and 
describe  what  you  see.  The  hollow  portion  here  is 
the  basin.  What  do  you  find  in  the  center  of  the 
basin?  What  is  this  the  remains  off 

,C  Cut  an  apple  cross- 

w  i  s  e  through  the 
middle.  How  many 
distinct  structures  do 
you  find?  What  is 
the  shape  of  the  core! 
How  many  cells  has 
it?  How  many  seeds 
in  a  cell?  Look  for 
the  core  line  which 
connects  the  points  of 
the  star.  Cut  an- 
other apple  length- 
wise .and  look  for  the  same  structures.  Trace  the 
core  line  from  the  cavity  to  the  basin.  In  which 
direction  do  the  seeds  point?  What  parts  of  the 
flower  produce  each  part  of  the  fruit?  Study  Fig.  51. 
An  apple  shows  something  of  all  parts  of  the  flower 
except  the  corolla.  The  stem  of  the  apple  is  the  stem 
of  the  flower  grown  somewhat  larger.  In  the  basin 


Fig.  52.  Section  of  an  apple  showing 
parts:  a,  Core  line;  b,  Core  with  seed 
cell  and  seed;  c,  Cavity;  d,  Basin;  e, 
Remains  of  calyx. 


FRUIT  AND  FRUIT  TREES  267 

are  the  dry  remains  of  the  sepals  and  often  a  few  of 
the  withered  stamens  and  styles.  The  core  is  the 
ripened  ovary  with  its  five  pointed  cells  which  con- 
tain the  seeds.  Around  the  core  is  the  receptacle 
which  has  become  thick  and  juicy  and  constitutes  the 
part  of  the  apple  that  is  eaten. 

History.  There  is  no  question  that  the  apple  is  the 
most  important  of  all  fruits.  It  is  probably  a  native  of 
southwestern  Asia.  It  has  been  cultivated  from  time 
immemorial,  probably  long  before  the  beginning  of 
written  history.  It  is  now  grown  in  all  countries 
situated  in  temperate  zones.  While  there  is  but  one 
species  known  as  Pyrus  mains,  there  are  hundreds 
of  varieties,  some  of  which  are  adapted  to  one  kind 
of  soil  and  climate,  others  to  different  conditions. 

Discussion.  The  apple  tree  does  not  grow  very  tall 
but  spreads  out  making  a  round  crown.  On  young 
trees  the  bark  is  quite  smooth  and  the  tree  rather 
symmetrical.  After  it  reaches  middle  age,  that  is, 
when  it  is  from  twenty  to  forty  years  of  age,  its 
branches  lengthen  very  slightly  each  year,  the  bark 
becomes  rough  and  shaggy,  and  the  whole  tree  has  a 
gnarled  appearance  that  makes  it  very  picturesque. 

Varieties  of  apples.  Bring  in  for  study  specimens 
of  different  varieties  of  apples.  Compare  them  as  to 
shape,  size  and  color.  Compare  two  apples  of  the 
same  variety  grown  in  different  parts  of  the  comma- 


268  STUDIES  IN  SCIENCE 

nity.  Group  the  apples  into  winter  and  fall  varie- 
ties. There  are  probably  no  summer  apples  left  at 
this  time.  What  is  the  most  striking  difference 
between  the  two  groups?  The  fall  apples  are  more 
mellow;  they  are  almost  ripe.  Winter  apples  are 
mature  but  will  ripen  later  in  the  season.  Apples 
are  mature  when  the  seeds  are  brown,  but  they  are 
not  ripe  till  the  pulp  is  soft,  mellow  and  juicy. 

Make  lists  of  different  varieties  of  apples,  group- 
ing them  according  to  the  time  they  mature,  as— 
Summer  apples:  duchess,  harvest,  early  June,  yellow 
transparent.  Fall  apples:  Grime's  golden,  snow, 
Jonathan,  maiden  blush,  bellflower,  wealthy.  Winter 
apples:  northern  spy,  wine  sap,  gano,  russet,  willow 
twig,  salome,  wolf  river,  stark,  Ben  Davis,  baldwin, 
greening,  spitzbergen,  Jeannet,  pippin. 

Picking,  storing  and  marketing.  Discuss  methods 
of  picking  and  storing  apples.  The  main  rule  to  fol- 
low in  picking  apples  is  not  to  bruise  them  or 
break  the  skin.  This  means  that  they  must  be  hand- 
picked,  not  shaken  from  the  tree.  Determine  whether 
all  the  apples  on  one  tree  are  equally  large,  well- 
shaped,  and  brightly  colored.  Look  for  any  that  are 
imperfect.  Apples  with  warty  knots  have  been 
affected  with  a  fungous  disease. 

Grade  your  apples  by  placing  together  the  finest, 
the  next  best,  and  so  on.  Firms  who  make  a  spe- 


FRUIT  AND  FRUIT  TREES  269 

cialty  of  selling  apples  have  several  grades.  One 
large  city  firm  grades  as  follows:  Extra  fancy,  in 
which  all  the  apples  are  perfect;  Fancy,  in  which  they 
are  nearly  perfect;  Choice,  good  fruit  but  not  all 
well-colored;  Number  two,  fruit  that  is  hand-picked 
but  varies  in  size  and  color;  however,  no  apple  less 
than  two  and  one-half  inches  in  diameter  is  consid- 
ered. Any  apple  smaller  or  less  perfect  than  Number 
two  is  called  a  cull. 

In  preparing  apples  for  market  some  are  packed  in 
barrels,  others  in  boxes.  When  apples  are  properly 
packed  they  lie  in  layers  and  there  are  no  large 
spaces  left  vacant.  The  apples  fit  close,  but  not  close 
enough  to  bruise  each  other.  Fancy  apples  from 
western  orchards  are  often  wrapped  singly  in  tissue 
paper  just  as  oranges  are. 

In  keeping  apples  in  your  home  over  winter  three 
conditions  are  essential:  First,  temperature;  the 
apples  should  be  kept  as  cool  as  possible.  A  tem- 
perature of  from  36°  to  40°  is  considered  good.  Sec- 
ond, ventilation;  they  should  be  placed  in  a  room 
where  there  is  plenty  of  fresh  air.  Third,  moisture; 
if  the  air  is  dry  the  apples  will  lose  their  freshness 
by  evaporation.  In  a  fruit  cellar  with  windows  all  of 
these  conditions  are  easily  secured.  Summer  and 
early  fall  apples  may  be  canned  or  dried  for  future 
use. 


270 


STUDIES  IN  SCIENCE 


Uses  and  distribution  of  apples.  Make  a  list  of 
all  the  different  ways  that  apples  may  be  cooked  and 
served  as  food.  Consult  your  geography  for  the 
apple  growing  regions  of  the  country.  How  impor- 
tant is  the  apple  growing  industry  in  your  own 
state? 

Other  fruits.     Make  a  comparative  study  of  other 

fruits  noting  resemblances 
and  differences.  Which  ones 
are  similar  in  structure  to 
the  apple?  Which  differ 
most  widely? 

The  apple,  quince,  pear 
and  crabs  resemble  each 
other  in  structure.  Each 
has  the  core  formed  from 
the  ovary  and  the  thickened 
receptacle  which  forms  the 
chief  part  of  the  fruit. 
This  kind  of  fruit  is  called 
a  pome. 

The  fruit  of  the  peach,  plum,  cherry  and  apricot 
is  known  as  a  drupe  or  stone  fruit.  In  this  the  inner 
wall  of  the  ovary  hardens  into  a  nutlike  covering 
which  encloses  the  seed.  The  outside  layer  thickens 
making  the  fleshy  part  that  is  used  for  food.  The 
orange  is  a  type  of  berry  with  a  thick,  leathery  skin. 


Fig.  53.  econ  o  a 
a,  Core  line;  b,  Seed  cell  and 
seed;  c,  Cavity;  d,  Basin;  e, 
The  withered  remains  of  the 
sepals  or  calyx. 


FRUIT  AND  FRUIT  TREES 


271 


This  tough  covering  is  a  great  advantage  to  growers 
of  oranges  since  it  is  possible  to  ship  the  fruit 
long  distances.  It  is  also  such  a  perfect  protection 
against  bacteria  and  mold  spores  that  the  fruit  keeps 
in  good  condition  many  weeks  with  little  care.  The 
skin  of  apples  and  of  other  fruits  is  a  protection 
against  germs  that  cause  decay.  It  also  prevents  the 
rapid  evaporation  cf  the  juices. 


Fig.    54.      Section    of   a    peach,    a    type   cf   drupe   or    stone   fruit.      A 
plum,    showing   resemblance    to   peach. 

The  peach.  The  peach,  too,  is  a  native  of  central  or 
south  Asia,  probably  of  Persia.  The  scientific  name  is 
Persica.  Peaches  are  not  grown  as  universally  as 
apples,  being  less  hardy.  They  require  a  rather 
warm  temperature.  In  most  cold  regions  the  trees 
die  during  the  winter,  and  even  in  regions  where 
the  trees  survive  severe  winters  the  fruit  or  flower 
buds  are  frequently  killed,  so  that  in  many  places 


272  STUDIES  IN  SCIUNC1S 

a  crop  of  peaches  is  produced  only  once  in  two 
or  three  years.  The  most  northerly  peach  grow- 
ing centers,  Michigan,  Maryland  and  Long  Island, 
have  their  climate  tempered  by  nearness  to  large 
bodies  of  water.  Peaches  are  grown  extensively  in 
warm  climates,  in  some  parts  of  Georgia  and  Texas 
and  in  other  southern  states,  as  well  as  on  the  Pacific 
coast.  There  are  two  chief  groups  of  peaches,  those 
with  white  pulp  and  those  with  yellow.  Some  of  the 
common  varieties  are — Yellow:  Elberta,  Crawford, 
Hale,  gold  drop,  Sincols  and  Fitzgerald.  White: 
Champion,  Carmen,  Greensborough,  and  Belle. 

Fruit  trees.  Make  a  special  study  of  your  apple 
orchards  and  other  fruit  trees.  Find  out  if  you  can 
how  old  the  orchard  is.  Look  carefully  at  the  trees. 
Are  any  of  them  broken?  Are  there  any  dead 
branches  or  suckers?  Select  one  tree  for  special 
observation.  How  tall  is  it?  You  may  estimate  the 
height  of  the  tree  by  measuring  your  own  height 
upon  the  trunk,  then  estimating  about  the  number  of 
times  the  tree  is  taller  than  you.  How  thick  is  the 
trunk?  What  is  the  color  of  the  bark?  Is  it  rough 
or  smooth?  What  is  the  shape  of  the  tree?  Com- 
pare young  and  old  trees  in  regard  to  appearance. 
If  there  are  apples  on  the  tree  notice  on  what  part 
of  the  branches  they  are  borne  and  how  they  are 
attached  to  the  twigs. 


FRUIT  AND  FRUIT  TREES  273 

Twigs.  Look  closely  at  a  twig  and  make  a  list  of 
everything  that  you  find.  How  do  the  new  and  old 
parts  differ?  Where  are  the  buds  situated?  How 
many  different  kinds  of  buds  are  present?  Determine 
if  possible  which  ones  will  produce  the  leaves  and 
which  the  flowers  in  the  spring. 

Compare  the  twigs  of  other  fruit  trees.  On  which 
do  you  find  bud  clusters?  How  many  in  one  cluster 
on  the  peach?  Plum?  Cherry? 

You  find  the  twigs  of  the  apple  tree  covered  with 
whitish  fuzz  with  buds  along  the  sides  and  at  the 
ends.  These  are  all  leaf  buds.  Here  and  there  you 
find  a  short  spur-like  twig  with  a  bud  at  the  end. 
That  is  the  flower  bud  that  will  produce  the  fruit 
next  year.  If  you  have  looked  carefully  at  your  apple 
trees  you  find  all  the  apples  attached  to  spurs. 

Propagation.  How  are  apple,  peach  and  all  other 
fruit  trees  propagated?  Most  people  who  have 
orchards  or  fruit  gardens  buy  young  trees  from  a 
nursery  and  transplant  them.  In  most  cases  this  is 
probably  the  wisest  thing  to  do.  But  if  you  are 
willing  to  wait  three  or  four  years  longer  for  your 
apples  and  pears  and  two  years  for  peaches,  cherries 
and  plums,  you  can  raise  your  trees  from  the 
beginning. 

Seeds  and  seedlings.  To  raise  an  apple  tree  the 
first  thing  to  do  is  to  plant  seeds.  Any  apple  seeds 


274  STUDIES  IN  SCIENCE 

will  do,  but  most  nursery  men  use  those  of  a  hardy, 
wild  apple  found  growing  on  the  hillsides  in  certain 
parts  of  France. 

Plant  the  seeds  in  drills  in  the  fall  or  early  spring. 
If  planted  in  the  spring  moisten  them  and  leave  them 
out  over  night  that  the  frost  may  aid  in  breaking  the 
hard  covering.  When  the  seedlings  come  up,  thin 
them  till  they  stand  about  three  inches  apart  in  the 
row.  Cultivate  during  the  summer  as  you  would 
any  garden  plant.  In  the  fall  remove  them  from 
the  ground,  cut  off  the  stems  leaving  about  eight 
or  nine  inches  attached  to  the  roots.  Tie  them  in 
bundles  and  place  in  moist  sand  or  moss  in  a  cool 
cellar. 

Grafting.  If  the  seeds  you  planted  were  from  a 
Jonathan  or  any  other  special  variety  of  apple  and 
you  allowed  the  seedlings  to  grow  until  they  were 
old  enough  to  bear  fruit,  the  apples  probably  would 
not  be  Jonathans  or  any  other  variety  that  you 
planted.  They  might  be  very  good,  but  the  proba- 
bility is  that  they  would  be  small,  sour,  inferior 
apples.  In  order  to  obtain  any  desired  variety  graft- 
ing is  necessary.  If  you  wish  a  Jonathan  apple  you 
must  graft  on  to  the  root  of  your  seedling  a  stem  or 
bud  taken  from  a  Jonathan  tree.  The  same  is  true, 
of  course,  of  any  other  variety  that  you  desire. 

The  root  or  part  on  which  the  graft  is  placed  is 


FRUIT  AND  FRUIT  TREES  275 

called  the  stock.  The  part  that  is  grafted  on  is  called 
the  scion.  It  is  very  essential  to  choose  the  scion 
from  a  tree  that  bears  well  and  that  has  excellent 
fmit,  for  your  grafted  tree  will  inherit  all  the  quali- 
ties of  the  tree  from  which  the  graft  is  taken.  You 
may  graft  at  any  time  during  the  winter  or  very  early 
spring.  Nurserymen  do  most  of  their  grafting  in 
January  and  February. 

To  make  the  graft,  first  cut  the  stems  from  the 
seedling  and  trim  all  the  branches  from  the  root. 
Now  make  a  long  diagonal  cut  near  the  upper  part 
of  the  root;  this  is  your  stock.  Choose  a  scion  of 
about  the  same  size.  Make  the  same  kind  of  cut. 
Now  make  a  slit  on  the  cut  surface  of  each  and  slip 
them  firmly  together.  See  Fig.  55. 

Use  great  care  to  see  that  the  layer  directly  under 
the  bark  of  the  scion  meets  the  same  layer  of  the 
stock.  This  is  essential  because  this  layer,  called  the 
cambium,  is  where  new  growth  occurs;  hence  this  is 
the  only  place  where  stock  and  scion  can  grow 
together.  The  next  step  is  to  wrap  grafting  thread 
or  raffia  firmly  around  the  graft.  Some  nurserymen 
cover  the  wound  with  grafting  wax.  When  you  have 
made  a  number  of  grafts  tie  them  together  and 
return  them  to  the  moist  sand  in  the  cellar.  Leave 
them  until  the  soil  is  in  good  condition  to  work  in 
the  spring,  then  set  them  out  in  rows  nine  or  ten 


276 


STUDIES  IN  SCIENCE 


inches  apart  and  deep  enough  so  that  two  or  three 
inches  of  the  scion  will  be  above  the  ground.  The 
scion  grows  fast  to  the  stock  and  then  grows  upward 
producing  the  little  apple  tree,  while  the  root  is  all 
that  is  left  of  the  seedling. 

When  the  little  tree  is  well  started  it  is  a  good 
thing  to  remove  some  of  the  buds  allowing  only  the 


Fig.  55.  Root  tongue-grafting.  A,  The  untrimmed  root  of  the  seed- 
ling; B,  Scion  trimmed  and  ready  to  be  inserted;  C,  Enlarged  section 
of  A  trimmed  and  slit  ready  to  receive  the  scion;  D,  Scion  inserted 
in  stock. 


stronger  ones  to  produce  the  tree.  Nurserymen  leave 
the  trees  from  two  to  three  years  in  the  nursery  row, 
then  they  are  ready  to  be  removed  and  set  out  in 


FRUIT  AND  FRUIT  TREES 


277 


the  orchard  or  fruit  garden.     The  kind  of  grafting 
just  described  is  known  as  root  tongue-grafting. 

In  some  apple  growing  regions  apples  are  propa- 
gated by  budding  instead  of  grafting.  Budding  is 
really  a  form  of  grafting  in  which  a  bud  of  the  desired 
variety  is  placed  on  the  stock  of  the  seedling.  Pears 
and  quinces  are  propagated  just  as  apples  are.  Some- 
times if  seedlings  are  scarce  nurserymen  make  three 
or  four  stocks  from  the  same  root,  cutting  it  into 
lengths  of  three  or  four  inches. 

Cleft  grafting  is  used  when 
one  wishes  to  graft  onto  a 
young  growing  tree  or  a 
branch  of  an  old  tree.  The 
stem  is  sawed  off  and  is  cleft 
split  across  the  center. 


or 

The  scion,  which  is  a  one- 
year  old  stem,  is  cut  wedge- 
shaped  a  little  thicker  on  one 
edge  than  the  other.  This  is 
inserted  into  the  cleft  with 
the  thicker  edge  outward,  so 
that  the  cambium  meets  the 
same  part  of  the  stock.  If 

the  stock  is  more  than  an  inch  thick  two  scions  are 
inserted,  one  in  each  side.  The  wounds  are  covered 
with  grafting  wax.  By  means  of  this  kind  of  grafting 


A  8 

Fig.  56.  Cleft  grafting.  A, 
The  stock  with  two  scions  in- 
serted; B,  The  same  with 
grafting  wax;  C,  In  place. 


278  STUDIES  IN  SCIENCE 

one  may  change  an  undesirable  variety  into  one  more 
desirable,  or  raise  several  different  varieties  of  fruit 
on  the  same  tree. 

How  long  will  it  be  after  the  tree  is  set  out  in  the 
orchard  before  it  will  produce  apples?  Different 
kinds  of  apples  vary  in  this  respect.  Some  produce 
apples  in  six  or  eight  years,  others  require  ten  to 
twelve  years.  You  see,  then,  that  to  make  an  apple 
tree  beginning  with  the  seed  requires  one  year  before 
it  is  ready  to  graft,  two  or  three  years  in  the  nursery 
row,  and  from  six  to  ten  years  in  the  orcliard  before 
it  bears  fruit.  How  long  will  an  apple  tree  continue 
to  bear  fruit !  You  have  perhaps  visited  at  your 
grandparents'  farm  where  there  is  an  orchard  still 
bearing  fruit  that  was  set  out  when  your  grandfather 
was  a  young  man.  Apple  trees,  if  well  taken  care  of, 
will  bear  from  twenty  to  fifty  years. 

Propagating  a  peach  tree.  You  can  easily  propa- 
gate a  peach  tree  of  any  desired  variety.  Plant  the 
seeds  in  the  fall  covering  them  lightly  so  that  freezing 
will  break  the  hard  shell.  In  the  spring  thin  to 
about  six  inches.  In  the  late  summer  or  early  fall 
bud  the  seedlings  just  where  they  stand  in  the  nursery 
row.  First  take  a  one-year  twig  from  the  variety 
of  peach  that  you  wish  to  produce.  Trim  off  the 
leaves  leaving  the  petioles  sticking  out  like  little 
stubs.  Nurservmen  call  this  a  "budding  stick."  In 


FRUIT  AND  FRUIT  TREES 


279 


the  bark  of  the  seedling  make  a,  T  slit  about  two 
inches  from  the  ground.  In  warm  climates  this  is 
always  made  on  the  north  side.  Cut  a  bud  from  the 
stick  with  a  slice  of  the  bark  and  a  little  wood,  and 
using  the  leaf  petiole  as  a  handle  slip  the  bud  into 
the  T  slit  pushing  it  well  down  and  covering  it  with 
the  little  flaps  of  bark  at  the  top.  "Wrap  with  raffia 
or  grafting  thread.  "See  Fig.  57.  It  is  often  well 
to  place  two  or  three  buds  in  the  same  stock.  If  the 
bud  does  well  it  will  grow  fast  to  the  stock  at  the 
cambium  layer.  In  the  spring  cut  off  the  top  of 


Fig.  57.  Budding.  A,  Budding  stick  with  one  bud  cut  out,  a; 
B,  Seedling1  tree  with  "T"  slit,  b ;  C,  Same  as  B  showing  flaps  of  bark 
folded  back;  D,  Bud  in  place;  E,  Bud  wrapped  with  cord  or  raffia. 

the   seedling   and   leave   the   strongest   bud   to   grow 
and  develop  into  your  peach  tree. 

In  the  fall  or  the  following  spring  the  tree  will 


280  STUDIES  IN  SCIENCE 

be  ready  to  transplant.  In  three  or  four  years  it  will 
bear  fruit. 

Orange  trees  also  are  propagated  by  budding. 
Seeds  from  the  sour  oranges  or  lemons  are  used  for 
the  stocks  because  they  are  hardier  than  those  of 
the  sweet  oranges.  Great  care  must  be  taken  to  plant 
the  seeds  as  soon  as  they  are  removed  from  the  fruit. 
If  they  are  allowed  to  dry  they  will  not  germinate. 
They  are  planted  in  rows  about  two  feet  apart.  After 
six  months  or  a  year  they  are  transplanted  to  rows 
from  three  to  four  feet  apart,  the  plants  standing 
about  ten  inches  apart.  At  the  end  of  three  or  four 
years  they  are  budded,  usually  in  the  fall.  After  a 
full  season's  growth  they  are  set  out  in  the  orchard 
and  in  three  years  are  beginning  to  bear  fruit. 

Cherries,  plums  and  prunes  are  propagated  by  bud- 
ding; pears  and  quinces  by  grafting  or  budding. 

CARE   or   FKUIT   TREES 

Cultivation.  How  far  apart  are  the  cherry  trees 
in  your  orchard  or  fruit  garden?  The  pears? 
Peaches?  Apples?  Oranges?  Lemons?  What  is  the 
condition  of  the  soil  between  the  rows?  Are  other 
plants  grown  here  ?  What  do  you  find  in  old  orchards  ? 
Young  ones?  Young  orchards  should  be  cultivated 
frequently  for  two  reasons :  1.  To  keep  down  weeds. 
2.  To  conserve  the  moisture. 


FRUIT  AND  FRUIT  TREES  281 

Pruning.  When  are  the  fruit  trees  in  your  neigh- 
borhood pruned?  Who  does  the  work?  What  tools 
are  used?  Why  is  pruning  necessary?  Examine  a 
pruned  tree.  Is  each  branch  cut  close  to  the  stem 
or  is  a  portion  left  as  a  stub?  Watch  the  scar  for  a 
number  of  weeks  to  find  out  how  it  heals.  What  has 
the  cambium  to  do  with  this?  Examine  an  old  scar. 

There  are  at  least  three  good  reasons  for  pruning 
fruit  trees :  1.  To  secure  a  well  formed  tree.  This 
means  proper  pruning  when  the  tree  is  young.  2.  To 
remove  superfluous  branches  or  suckers  so  that  the 
fruit  bearing  branches  may  get  more  nourishment. 
3.  To  keep  the  tree  free  from  old,  non-bearing  stems 
and  branches.  A  well  pruned  tree  has  just  enough 
branches  to  permit  the  free  circulation  of  air  and  the 
right  amount  of  sunlight. 

The  usual  time  to  prune  is  in  late  winter  or  early 
spring.  Some  fruit  growers,  however,  prune  in  the 
summer.  To  prune  moderately  each  year  is  better 
than  to  prune  heavily  every  three  or  four  years. 

A  good  pruner  removes  the  branch  close  to  the 
stem  from  which  it  grows.  A  stub  should  never  be 
left  sticking  out  from  the  stem.  It  does  not  heal 
quickly  and  is  likely  to  foster  the  growth  of  fungous 
diseases.  From  your  study  of  an  apple  tree  you  know 
that  spurs  grow  out  from  the  sides  of  the  branches 
and  produce  the  next  year's  fruit.  Care  must  be 


282  STUDIES  IN  SCIENCE 

taken  not  to  remove  too  many  spurs  and  thus  reduce 
the  crop. 

Spraying.  Make  a  list  of  insect  enemies  of  fruit 
trees.  A  list  of  fungous  diseases.  How  may  these 
be  combated?  What  different  kinds  of  sprays  have 
you  seen?  What  time  of  year  are  the  trees  sprayed? 
What  materials  are  used? 

A  mixture  designed  to  kill  insects  is  called  an 
insecticide;  one  to  kill  fungi  is  a  fungicide. 

In  treating  fruit  trees  a  fungicide  and  insecticide 
are  frequently  combined  and  sprayed  together.  Some 
common  mixtures  are  arsenate  of  lead  and  lime-sul- 
phur; arsenate  of  lead  and  Bordeaux  mixture;  Paris 
green  and  Bordeaux  mixture. 

Fruit  projects.  Plan  to  care  for  your  fruit  trees 
if  you  have  an  orchard.  Look  after  the  spraying  and 
pruning.  If  you  lack  time  to  care  for  the  entire 
orchard  choose  three  or  four  trees  and  see  whether 
you  can  improve  the  quantity  and  quality  of  the  fru?t 
by  your  care.  Keep  a  record  of  your  expenditures, 
receipts  and  profits.  Determine  from  your  experience 
whether  it  pays  to  give  some  time  to  the  care  of  fruit 
trees. 


CHAPTER  XVIII 

DOMESTIC  ANIMALS 

1.     CATTLE 

Material,  Cows  of  the  community,  milk,  Babcock 
tester,  pictures  of  different  breeds  of  cattle. 

Study.  Cattle  may  be  grouped  into  two  great 
classes;  those  kept  for  dairy  purposes,  known  as 
dairy  cattle,  and  those  raised  for  meat,  known  as  beef 
cattle.  Decide  what  kinds  are  found  in  your  commu- 
nity. 

Make  a  careful  study  of  a  cow.  Write  the  names 
of  the  different  parts  of  the  body.  Note  the  shape 
of  the  body  and  the  height.  What  sense  organs  have 
cows!  Describe  the  eyes,  ears,  nose.  Watch  the  cow 
crop  grass.  How  does  she  do  itf  Watch  her  chew- 
ing her  cud.  Explain  the  movements  that  you  see 
in  the  neck  at  this  time. 

Describe  her  feet  and  legs.  Locate  the  joints  in 
the  fore  leg  that  correspond  to  those  in  your  arm. 
Locate  those  in  the  hind  leg  that  correspond  to  those 

283 


284  STUDIES  IN  SCIENCE 

in  your  leg.  How  many  toes  can  you  find!  How 
many  are  used  to  walk  upon? 

Discussion.  In  order  to  talk  intelligently  about  a 
cow  and  to  make  a  score-card  for  judging  cattle  the 
various  parts  have  been  given  names.  See  Fig.  58. 

You  find  that  the  eyes  of  a  cow  are  situated  so 


Fig.  58.    Diagram  showing  external  parts  of  a  cow. 

1.  Muzzle.  2.  Jaw.  3.  Face.  4.  Fore-head.  5.  Throat.  6.  Neck. 
7.  Withers.  8.  Shoulder.  9.  Chest.  10.  Back.  11.  Ribs.  12.  Loin. 
13.  Rump.  14.  Rump.  15.  Hips.  16.  Tail.  17.  Thigh.  18.  Udder. 
19.  Belly.  20.  Milk  Veins. 

that  she  has  a  fair  range  of  vision  in  all  directions. 
She  can  turn  her  ears  in  any  direction  to  catch  sounds. 
Her  hearing  is  very  keen.  The  sense  of  smell  seems 
well  developed  also.  It  is  perhaps  aided  by  the  mois- 
ture which  always  stands  on  her  nose.  What  animal 


DOMESTIC  ANIMALS  285 

that  uses  its  sense  of  smell  a  great  deal  has  a  cool, 
moist  nose? 

Cows  eat  rapidly  and  swallow  their  food  after 
chewing  it  very  slightly.  This  food  passes  into  the 
first  stomach.  From  here  it  goes  into  a  small  apart- 
ment where  it  is  made  into  balls.  The  cow  then  lies 
down  or  stands  quietly  while  she  brings  back  to  the 
mouth  one  ball  of  food  after  another,  chews  it5  and 
swallows  it  again.  This  is  called  chewing  the  cud. 
This  time  it  goes  into  the  true,  stomach  where  it  is 
digested.  You  can  see  the  balls  of  food  move  upward 
along  the  neck.  If  you  look  into  a  cow's  mouth  you 
find  eight  front  teeth  on  the  lower  jaw.  There  are 
no  front  teeth  on  the  upper  jaw.  Instead,  there  is  a 
hard  plate.  There  is  a  space  without  teeth  on  the 
lower  jaw.  Each  jaw  has  twelve  grinding  teeth,  six  on 
each  side. 

The  cow  walks  on  two  toes.  Above  these  you  can 
see  two  other  toes.  The  first  joint  in  the  front  leg 
that  looks  as  if  it  might  be  the  knee  corresponds  to 
your  wrist.  The  elbow  joint  is  up  near  the  body, 
while  the  shoulder  joint  is  about  half  way  up  the  side 
of  the  body.  The  ankle,  knee  and  hip  joints  occupy 
similar  positions  in  the  hind  leg. 

A  dairy  cow  differs  in  shape  from  a  beef  cow.  She 
is  said  to  be  wedge-shaped.  The  wide  part  of  the 
wedge  is  at  the  back,  the  narrow  part  or  point  in 


286 


STUDIES  IN  SCIENCE 


front.  A  good  dairyman  looks  for  other  characteris- 
tics. The  cow  must  have  what  he  calls  open  confor- 
mation; that  is,  a  wide  space  between  the  hip  bones, 
the  ribs  wide  and  far  apart,  the  vertebrae  long,  and 
the  paunch  large  and  deep.  She  must  also  have  dis- 
tinct dairy  qualities;  the  skin  loose,  dry,  and  flexible, 
the  hair  soft  and  silky,  the  eyes  bright  and  project- 


rig.  59.     A  dairy  cow. 

ing  a  little,  the  face  smooth  and  the  head  well  pro- 
portioned. The  udder  must  be  flat  across  the  bot- 
tom, attached  high  in  the  rear,  and  extending  well 
forward. 

The  form  of  the  beef  cow  makes  possible  the  taking 
on  of  a  large  amount  of  flesh.    A  beef  cow  is  almost 


DOMESTIC  ANIMALS  287 

rectangular  in  form,  with  a  short  heavy  neck  and  short 
legs.  The  body  has  a  smooth,  compact  appearance. 

Dairy  breeds.  Make  a  list  of  the  dairy  breeds  you 
know.  Look  through  farm  journals  and  other  papers 
for  pictures  of  different  breeds  of  cattle.  Cut  these 
out  and  group  them  to  form  a  booklet. 

The  common  dairy  breeds  are  Jersey,  Guernsey, 
Holstein-Friesian  and  Ayrshire. 

Jersey  cattle  came  originally  from  Jersey  Island 
in  the  English  Channel.  They  are  small  cows  of  a 
fawn  or  grayish  brown  color,  shading  toward  black 
at  the  head  and  feet  and  along  the  back.  They  have 
black  noses. 

Guernsey  cattle  originated  on  Guernsey  Island  not 
far  from  Jersey.  They  are  a  little  larger  than  the 
Jersey,  are  about  the  same  color  but  frequently  have 
white  markings,  with  flesh  colored  noses.  These  two 
breeds  are  similar  in  the  quality  of  milk,  both  giving 
a  rather  small  quantity  but  very  rich  in  butter  fat. 
The  Jerseys  are  numerous  in  central  and  southern 
United  States,  the  Guernseys  in  the  northern  states 
and  Canada. 

Ayrshire  cattle  came  originally  from  the  county 
of  Ayr  in  Scotland.  They  are  larger  than  the  Jer- 
seys, are  smooth,  well  formed  cattle.  The  color  is 
white  with  spots  and  streaks  of  red. 

Holstein-Friesian   came   from   Holland.     They   are 


288  STUDIES  IN  SCIENCE 

much  larger  than  the  other  dairy  breeds,  and  are 
black  and  white  in  color.  They  are  the  greatest  milk 
producers,  but  their  milk  is  usually  rather  low  in 
butter  fat. 

Care  and  food  of  dairy  cattle.  What  food  do  dairy 
cows  eat  during  the  summer?  During  the  winter? 
Make  a  list  of  the  different  kinds  of  food  used. 

In  some  localities  cows  subsist  during  the  summer 
almost  wholly  upon  pastures.  In  other  places  dairy- 
men do  not  use  pastures  at  all  but  feed  soiling  crops 
and  grains  during  the  summer.  In  the  winter  hay  of 
different  kinds,  grains,  silage,  and  ground  feeds  are 
used. 

It  is  very  important  that  cows  be  fed  properly  if 
they  are  to  keep  in  good  condition  and  give  a  profit- 
able amount  of  milk.  They  must  have  enough  food 
and  the  proper  kinds.  This  means  that  they  must 
have  the  right  proportion  of  protein,  carbohydrates 
and  fat. 

Protein  is  necessary  for  the  making  of  muscle, 
blood,  connective  tissue  and  the  protein  part  of  milk. 
It  should  constitute  r.t  least  one-sixth  of  a  cow's 
ration  during  the  milking  season.  It  may  be  sup- 
plied by  any  of  the  following  foods:  alfalfa,  clover, 
cow-peas,  soybeans,  bran,  cotton-seed  meal,  linseed 
meal,  and  oats. 

Carbohydrates   and  fats  are.  required  for  energy, 


DOMESTIC  ANIMALS  289 

heat,  fat  for  the  body,  sugar  and  fat  for  milk.  Fats 
are  found  to  some  extent  in  all  feeds.  The  common 
carbohydrate  feeds  are  corn,  silage,  oat  straw,  sugar 
beets,  and  beet  pulp. 

When  these  foods  are  fed  in  the  proper  proportion 
they  are  said  to  form  a  balanced  ration.  Many 
agricultural  stations  have  worked  out  tables  of  bal- 
anced rations  for  the  use  of  dairymen  and  other 
farmers. 

The  following  two  tables  were  arranged  by  the 
Purdue  Agricultural  College: 

Ration  I  Ration  II 

Corn  silage  30  pounds  Sugar  beets   25  pounds 

Cow-pea  hay 10  pounds  Alfalfa  hay  . 10  pounds 

Corn  stover 2  pounds  Corn  stover 5  pounds 

Corn 6  pounds  Corn   5  pounds 

Cotton-seed  meal  ....1.5  pounds  Dried  brewer's  grains.. 5  pounds 

A  good  dairyman,  however,  compounds  his  own 
rations  to  fit  the  weight  and  milk  production  of  his 
individual  cows.  Usually  a  cow  should  be  given  1 
pound  of  leguminous  hay  and  3  pounds  of  silage  for 
each  100  pounds  of  live  weight,  and  1  pound  of  grain 
for  each  3  pounds  of  milk  produced. 

Beef  cattle.  There  are  several  different  breeds  in 
America.  Shorthorns  are  probably  the  most  widely 
raised  due  to  the  fact  that  many  of  them  produce 
a  fair  amount  of  milk  as  well  as  beef.  They  are  of  dif- 
ferent colors,  some  red,  some  red  and  white,  some 


290  STUDIES  IN  SCIENCE 

roan,  and  some  almost  pure  white.  The  red  ones  are 
probably  the  most  numerous.  They  are  sometimes 
called  Durhams. 

Herefords  are  becoming  more  and  more  common 
in  many  parts  of  the  country.     They  are  the  cattle 


Fig.  60.     A  beef  cow. 

you  often  see  in  pastures  with  red  bodies  and  white 
faces  and  legs. 

We  have  two  kinds  of  black  cattle,  Aberdeen- Angus 
and  Galloways.  The  Angus  are  heavier  than  the 
Galloways.  During  the  winter  the  coats  of  the  latter 
become  very  long  and  shaggy. 

The  food  of  beef  cattle.  The  food  of  beef  cattle 
also  should  receive  special  attention.  Since  the 
object  is  to  produce  the  greatest  amount  of  meat  pos- 
sible, a  ration  is  planned  with  this  in  view.  More 


DOMESTIC  ANIMALS  291 

carbohydrates  and  fats  are  fed  in  proportion  to  the 
protein  to  beef  cattle  than  to  dairy  cows.  Instead 
of  feeding  all  grain,  silage  mixed  with  concentrated 
foods  as  linseed  meal,  cotton-seed  meal  and  gluten  is 
coming  more  and  more  into  use. 

Housing  cattle.  Housing  cattle  properly  is  quite 
as  important  as  good  food.  A  cow  barn  should  be 
built  so  that  the  cows  will  have  plenty  of  air  and 
light  and  be  comfortably  warm.  It  should  also  be 
constructed  with  the  idea  of  cleanliness.  The  best 
barns  have  hard  floors,  usually  cement.  The  stalls 
have  a  shallow  gutter  at  the  back  which  slopes 
slightly  to  one  end  so  that  it  may  be  washed  out  eas- 
ily with  a  hose.  In  front  is  a  water-tight  trough  used 
for  food.  This  too  has  a  slight  slope  and  may  be 
easily  washed  out. 

Composition  of  milk.  Of  what  is  milk  composed? 
You  know  by  tasting  that  it  is  sweet.  This  means 
that  it  has  sugar  in  it.  We  call  this  milk-sugar. 
Another  of  the  important  ingredients  is  fat.  This 
is  known  as  butter  fat.  There  is  also  some  protein 
in  it  and  a  very  small  amount  of  minerals.  All  the 
rest  of  the  milk,  by  far  the  largest  part,  is  water. 

The  following  table  shows  approximately  the  pro- 
portions of  each  ingredient  in  milk  of  average  quality : 

Butter  fat   4.0  per  cent 

Proteid  .  ,  3.3    "      " 


292  STUDIES  IN  SCIENCE 

Sugar 5.0  "  '" 

Minerals .7  "  " 

Water 87.0  "  " 

£..  ~  • 

Experiment.  Place  some  fresh  milk  in  a  bottle, 
straight  tumbler,  or  test  tube.  Allow  it  to  stand  a 
few  hours.  What  happens!  Why  does  the  cream 
come  to  the  top  1  What  does  a  piece  of  wood  do  when 
put  into  water!  Why  does  it  float  upon  the  water! 
Cream  comes  to  the  top  of  milk  for  the  same  rea- 
son; that  is,  because  it  is  lighter  than  milk.  Measure 
the  height  of  the  milk,  of  the  cream.  Calculate  what 
per  cent  is  cream.  Cream  is  largely  butter  fat. 

Separation.  What  methods  are  used  in  separating 
cream  from  milk !  Some  people  use  crocks  or  shallow 
pans.  Fresh  milk  is  put  into  these  and  allowed  to 
stand.  The  cream  rises  to  the  top  and  is  then  skimmed 
off  with  a  flat  skimmer.  This  is  the  old-fashioned 
method  but  is  still  used  by  many  people.  It  is  by  far 
the  poorest  method  known.  It  has  been  estimated  that 
at  least  one-fourth  of  the  butter  fat  is  left  in  the 
skimmed  milk  when  this  method  is  used. 

Some  people  use  a  deep  can,  at  least  twenty  inches 
in  depth.  The  milk  is  placed  in  it  and  is  usually  kept 
cool  by  placing  the  can  in  water.  Sometimes  the 
cream  is  skimmed  off  as  it  is  from  the  shallow  pans, 
but  a  better  wav  is  to  have  a  faucet  in  the  bottom 


DOMESTIC  ANIMALS  293 

of  the  can.  When  the  cream  has  risen  the  faucet  is 
turned  and  the  milk  is  drained  off.  Then  the  cream 
is  drawn  off  through  the  faucet.  Much  more  butter 
fat  is  obtained  in  this  way  than  by  the  shallow  pan 
method. 

Many  people  use  a  separator  by  which  the  milk 
and  cream  may  be  separated  at  once  without  allowing 
the  milk  to  stand.  A  separator  is  a  machine  which 
is  worked  by  means  of  a  crank.  The  main  part  is  a 
cylindrical  bowl  that  revolves  rapidly.  The  milk  is 
placed  in  this  bowl.  What  happens  to  the  milk  in 
this  cylinder!  Tie  a  piece  of  chalk  or  some  other 
object  to  a  string  about  eighteen  inches  in  length. 
Take  hold  of  the  end  of  the  string  and  whirl  it  rap- 
idly.  Can  you  feel  the  string  pulling?  Let  go  while 
you  are  whirling.  What  do  the  string  and  weight 
do?  The  force  that  made  the  string  pull  on  your 
hand  and  caused  it  to  fly  off  in  a  straight  line  when 
you  let  it  go  is  called  centrifugal  force.  It  is  the 
force  that  causes  revolving  bodies  everywhere  to 
move  away  from  the  center.  Did  you  ever  notice 
how  mud  .and  water  fly  from  a  rapidly  revolving 
wheel  f  Since  milk  is  heavier  than  cream,  which  will 
move  more  rapidly  away  from  the  revolving  center? 
You  can  readily  see  that  since  the  milk  is  heavier 
it  will  move  toward  the  outside  of  the  cylinder  while 
the  cream  is  forced  toward  the  inside.  There  is  an 


294  STUDIES  IN  SCIENCE 

opening  toward  the  outside  through  which  the  milk 
pours  out  in  a  stream  and  an  opening  toward  the 
inside  through  which  the  cream  pours  forth. 

In  many  country  districts  milk  is  sent  directly  to 
a  creamery  instead  of  being  separated  at  home.  In 
many  places  large  cans  are  furnished  by  creamery 
companies.  A  man  comes  around  once  each  day, 
collects  the  cans  of  milk,  and  takes  them  to  the 
creamery.  The  cream  and  the  milk  are  separated  at 
once,  and  usually  the  milk  is  put  back  into  the  cans 
and  returned  to  the  farms,  where  it  is  used  to  feed 
calves  and  pigs.  What  is  done  with  the  cream  at  the 
creamery?  What  is  usually  done  with  the  cream  that 
is  kept  at  home? 

Butter.  Is  butter  made  from  sweet  or  sour  cream? 
You  know  from  your  study  of  bacteria  that  there  are 
organisms  which  under  right  conditions  cause  milk 
and  cream  to  sour.  Sour  cream  makes  better  flavored 
butter  than  sweet  cream.  In  homes  the  cream  is 
allowed  to  stand  until  it  sours  or  ''ripens."  In  cream- 
eries a  small  amount  of  sour  cream,  or  other  substance 
containing  a  number  of  cream-souring  bacteria  called 
a  starter,  is  placed  in  the  fresh  cream  so  that  it 
ripens  in  a  short  time. 

Describe  different  kinds  of  churns  that  you  have 
seen.  What  is  the  principle  of  churning?  The  cream 
is  agitated  violently  enough  to  force  the  fat  particles 


DOMESTIC  ANIMALS  295 

together.  They  strike  against  each  other  and  adhere, 
the  particles  growing  larger  and  larger.  It  is  not 
best  to  continue  churning  until  the  particles  are  all 
joined  together  in  one  great  mass.  Churning  should 
be  stopped  when  the  particles  are  not  much  larger 
than  a  pea.  If  the  masses  are  too  large  it  is  much 
harder  to  remove  all  the  milk  and  water  from  the 
butter. 

Care  of  milk.  Besides  the  bacteria  which  cause 
milk  to  sour,  there  are  likely  to  be  many  other  kinds 
in  milk,  some  of  which  produce  diseases.  Since  bac- 
teria find  milk  a  favorite  field,  what  care  should  be 
taken  to  prevent  too  many  of  them  from  getting  into 
it?  First  of  all,  great  care  should  be  exercised  in 
milkitfg.  The  milker  should  have  clean  clothing  and 
clean  hands.  The  cow  should  be  brushed  to  get  rid 
of  dust,  and  the  udder  should  be  washed  or  wiped 
clean.  A  covered  milk  pail  is  preferable  to  an  open 
one.  It  is  made  with  an  opening  just  large  enough 
to  allow  the  stream  of  milk  to  flow  in. 

The  second  step  in  caring  for  milk  is  straining. 
A  wire  strainer  should  not  be  used.  Cheesecloth  and 
absorbent  cotton  make  the  best  strainers.  A  layer 
of  cotton  is  placed  between  two  or  four  folds  of 
cheese  cloth.  The  cotton  should  be  destroyed  after 
using  once.  The  cheesecloth  should  be  scalded  and 
placed  in  the  sun.  When  possible  all  other  utensils 


296  STUDIES  IN  SCIENCE 

used  with  the  milk  should  be  cleansed  in  a  similar 
manner. 

The  third  step  is  cooling.  Milk  should  be  cooled 
as.  quickly  as  possible.  The  best  dairy  farms  have  a 
special  apparatus  for  cooling  milk  rapidly. 

Experiment.  To  determine  the  effect  of  cooling 
upon  the  growth  of  bacteria  in  milk. 

Divide  a  cupful  of  new  milk  into  two  equal  parts 
putting  half  into  a  bottle  numbered  one,  the  other 
half  into  a  bottle  numbered  two.  Place  the  first 
bottle  at  once  into  a  pan  of  very  cold  water.  Leave 
the  other  in  the  room.  When  bottle  number  one  is 
thoroughly  cooled  stand  it  beside  number  two  and 
compare  as  to  appearance.  Which  sours  first?  Give 
reasons. 

The  prompt  cooling  retarded  the  growth  of  bac- 
teria that  were  in  the  milk.  In  number  two  the  bac- 
teria began  at  once  to  feed  and  multiply  causing 
the  milk  to  sour. 

Testing  the  milk.  In  order  to  determine  whether 
or  not  a  cow  is  producing  enough  milk  and  butter  fat 
to  make  her  a  profitable  investment,  the  amount  of 
milk  should  be  weighed.  This  means  that  the  milk  of 
each  cow  should  be  weighed  separately  and  a  record 
kept.  Every  good  dairy,  or  farm  where  a  number  of 
cows  are  kept,  has  a  pair  of  scales  hanging  in  a  con- 
venient place  with  a  sheet  of  paper  for  recording 


DOMESTIC  ANIMALS  297 

weights  of  milk.  At  the  end  of  a  season  the  dairy- 
man can  easily  determine  which  cows  are  worth 
keeping  and  which  are  not. 

To  determine  the  amount  of  butter  fat  that  a  cow 
produces  frequent  tests  with  the  Babcock  tester  are 
necessary.  This  tester  may  be  bought  for  from  four 
to  ten  dollars  depending  upon  the  number  of  bottles. 
Directions  for  using  come  with  each  machine.  Any 
seventh  or  eighth  grade  boy  or  girl  can  soon  learn 
to  use  the  tester.  The  milk  of  each  cow  should  be 
tested  at  least  once  a  month.  It  will  be  interesting  to 
test  skimmed  milk  from  a  shallow  pan,  a  deep  can, 
and  a  separator  to  determine  which  method  leaves  the 
least  fat  in  the  milk. 

Milk  and  health.  Milk  provides  one  of  the  most 
important  foods  for.  mankind.  It  is  especially  valua- 
ble for  children  since  it  contains  all  of  the  food 
nutrients  needed  by  the  growing  child.  Thousands 
of  children  are  more  or  less  dependent  upon  it  for 
food. 

Cattle  are  subject  to  the  dread  disease,  tuberculosis, 
and  a  cow  that  has  this  disease  may  infect  human 
beings  through  her  milk.  In  many  places  herds  are 
carefully  inspected  and  once  a  year  given  the  tuber- 
culin test  which  makes  it  possible  to  detect  any  indi- 
viduals that  have  the  disease.  These  are  isolated 
from  the  herd  and  in  some  cases  killed. 


298  STUDIES  IN  SCIENCE 

Milk  that  is  suspected  of  containing  tubercular 
bacteria  should  be  sterilized  or  pasteurized. 

Sterilization  kills  all  the  bacteria,  but  boiling 
changes  the  flavor  and  digestibility  of  milk  and  is 
not  very  desirable.  Pasteurization  kills  all  active 
bacteria,  The  bacterial  spores,  which  are  inactive, 
are  not  killed  and  in  time  become  active  and  cause 
the  milk  to  sour.  However,  bacteria  spreading  such 
diseases  as  tuberculosis,  typhoid,  etc.,  do  not  have 
the  spore  forms  and  are  all  killed  by  this  process. 

Value  of  cattle.  Make  a  list  of  the  uses  of  cattle, 
and  of  the  industries  that  are  dependent  upon  them. 
These  two  lists  will  help  you  to  realize  how  valuable 
cattle  are.  The  most  important  products  are  milk, 
meat,  and  leather.  Some  of  the  different  milk  prod- 
ucts are  butter,  cheese,  condensed  milk,  milk  powders, 
and  ice  cream.  There  are  a  large  number  of  by- 
products. Fertilizers  are  made  from  blood  and  bones, 
the  hair  is  used  in  upholstering,  brush  handles  and 
buttons  are  made  from  horn  and  bone,  glue  and  gela- 
tin are  made  from  the  hoofs  and  connective  tissue. 

Projects.  If  you  live  in  the  country  you  may  easily 
undertake  one  or  two  projects  in  connection  with  your 
cattle  study. 

The  calf  project  is  one  suggested  by  the  Depart- 
ment of  Agriculture  that  may  interest  boys  and  girls. 
Take  a  young  calf,  care  for  it  for  a  year  or  six 


DOMESTIC  ANIMALS  299 

months.  Keep  a  careful  record  of  the  feed,  amount 
and  cost. 

Find  the  gain  in  pounds  at  the  end  of  the  period 
and  the  cost  per  pound  of  gain. 

Keep  a  record  also  of  the  difficulties  you  meet  and 
how  you  overcome  them.  Note  any  other  facts  of 
interest  that  you  learn  in  raising  your  calf 

A  second  project  that  is  worth  while  is  testing 
milk  for  butter  fat  with  the  Babcock  tester.  Several 
cows  should  be  chosen  and  tests  made  of  the  milk. 
To  make  a  fair  test,  samples  of  milk  from  each  cow 
for  four  consecutive  milkings  should  be  tested  once 
a  month.  Careful  records  should  be  kept  and  con- 
clusions drawn  as  to  the  quantity  of  butter  fat  pro- 
duced by  each  cow  in  a  given  time. 

Still  another  valuable  project  is  testing  cows  for 
amount  of  milk  produced.  This  means  taking  daily 
weights  of  the  milk  from  each  cow  for  six  months 
or  any  definite  period  agreed  upon. 

2.  HORSES 

Types  of  horses.  Observe  the  horses  in  your  com- 
munity. Are  they  all  of  the  same  kind  or  breed? 
State  some  of  the  differences  as  to  size,  build  and 
color  that  you  have  noticed.  These  differences  indi- 
cate to  some  extent  the  differences  in  breed.  There 
are  three  important  types  of  horses  known :  the  draft 


300 


STUDIES  IN  SCIENCE 


horse,  the  coach  or  carriage  horse,  and  the  roadster 
or  trotter. 

The  draft  horse  is  heavy,  has  rather  short,  heavy 
legs,  a  short,  thick  neck  and  broad,  deep  chest 
and  shoulders.  There  are  two  other  classes  of  heavy 
horses  that  are  closely  related  to  the  draft  breeds. 


Fig.  61.    A  good  farm  team. 

These  are  known  as  chunks  and  wagon  horses. 
Chunks  are  light  weight  draft  horses.  Wagon  horses 
are  rather  heavy  but  more  active  than  the  draft  or 
chunks.  Artillery  horses  and  those  used  in  fire 
departments  are  of  this  type. 


DOMESTIC  ANIMALS  301 

Carriage  horses  are  not  common  in  America.  More 
attention  is  given  to  raising  them  in  the  East  and 
South  than  in  the  West.  These  horses  are  somewhat 
lighter  than  wagon  horses,  have  long  arched  necks, 
and  are  usually  of  graceful  appearance. 

The  third  type,  the  roadster,  is  a  tall  slender  horse 
with  a  small  head,  a  long  neck,  and  a  rather  thin 
light  body. 

What  is  the  use  of  the  roadster?  The  name,  of 
course,  suggests  the  use.  This  horse  must  be  able 
to  travel  rapidly  and  endure  the  strain  of  travel 
for  a  long  time.  Why  should  a  roadster  be  much 
lighter  in  weight  than  a  draft  or  work  horse?  Do 
you  know  of  any  true  carriage  horses  in  your  neigh- 
borhood? How  do  they  compare  with  the  heavy 
work  horses  and  the  roadsters? 

Uses  of  horses.  Observe  horses  in  the  neighbor- 
hood and  note  which  seem  to  fit  the  description  of  any 
of  these  various  types.  Look  in  farm  papers  and 
magazines  for  pictures  of;  horses  of  different  kinds 
and  start  a  chart  of  these  as  you  did  of  the  different 
breeds  of  cattle.  What  are  the  uses  of  the  different 
kinds?  The  largest  draft  horses  are  used  in  large 
cities  to  draw  immense  loads  of  various  kinds.  Do 
you  know  how  much  a  heavy  draft  horse  weighs? 
The  heaviest  draft  horses  weigh  over  2,000  pounds, 
medium  drafts  from  1,600  to  1,700  pounds,  and  light 


302  STUDIES  IN  SCIENCE 

draft  from  1,500  to  1,600  pounds.  Do  these  horses 
move  rapidly  or  slowly? 

Make  a  list  of  the  different  kinds  of  work  that 
farm  horses  do.  Is  any  work  now  done  by  horses  that 
was  once  done  by  man?  Inquire  of  your  parents  in 
regard  to  this  matter.  Perhaps  some  of  them  will 
remember  when  corn  was  planted  by  hand  and  all 
small  grains  sowed  broadcast  by  hand.  To  what 
extent  have  gasoline  or  steam  engines  taken  the 
place  of  horse  power  in  your  neighborhood?  Think 
of  tractors,  threshers,  corn-shellers,  automobiles,  etc. 
While  you  do  not  remember,  your  parents  will,  that 
not  many  years  ago  all  threshing  machines  and  corn- 
shellers  were  run  by  horse  power. 

Description.  Study  a  horse.  Use  good  pictures  if 
you  do  not  have  an  opportunity  to  study  a  live  horse. 
Make  a  list  of  the  parts  with  a  description  of  each. 
How  high  is  the  horse?  Compare  the  length  of  the 
legs  with  the  height.  Note  movements  of  the  ears. 
What  is  the  advantage  in  the  position  of  the  ears? 
Describe  the  eyes,  the  nostrils.  Note  the  thick  lips 
and  the  teeth.  How  many  front  teeth  do  you  see? 
Note  the  body  covering.  What  are  the  uses  of  the 
mane  and  tail? 

Examine  the  feet  and  legs.  Note  differences 
between  the  front  and  hind  legs.  Determine  the  joints 
corresponding  to  those  in  your  own  body.  Show  how 


DOMESTIC  ANIMALS  303 

the  leg  and  foot  of  a  horse  are  adapted  for  speed  and 
for  travel  upon  dry  ground.  How  does  the  tail  differ 
from  that  of  the  cow!  Compare  the  foot  of  the 
horse  with  that  of  the  cow.  Which  foot  will  endure 
more  travel  on  hard  ground!  Which  will  likely  bear 
the  animal  up  better  on  soft  ground!  Why! 

Discussion.  The  horse  is  among  the  best  loved 
of  all  domestic  animals.  In  some  ways  it  seems  more 
intelligent  than  other  animals.  It  is  high-spirited 
and  sensitive.  You  noticed  how  the  ears  move  as  if 
they  were  on  a  pivot,  ready  to  catch  every  sound. 
The  eyes  are  placed  so  as  to  give  a  wride  range  of 
vision.  The  nostrils  flare.  The  sense  of  smell  is  very 
keen.  The  long  legs  and  comparatively  light  body 
show  that  the  horse  is  well  adapted  for  travel.  The 
height  of  a  horse  is  measured  in  hands.  One  hand 
is  four  inches. 

The  teeth  of  the  horse  are  interesting.  When  a 
horse  is  full  grow^n  he  has  forty  teeth.  On  each  jaw 
there  are  six  incisors,  two  canines,  and  twelve  molars. 
The  incisors  are  prominent  and  sharp  enabling  the 
horse  to  crop  grass  very  close  to  the  ground.  A  man 
who  knows  horses  can  tell  the  age  of  a  horse  by  exam- 
ining the  incisors.  A  colt's  teeth  are  temporary  and 
are  gradually  replaced  by  the  permanent  set. 

The  middle  pairs  of  permanent  incisors,  above  and 
below,  appear  when  the  horse  is  three  years  old;  the 


304  STUDIES  IN  SCIENCE 

next  pair  at  four,  and  the  third  pair  at  five  years. 
The  new  teeth  have  deep  cups  or  indentations  in  the 
middle  of  the  biting  surface.  As  the  teeth  are  used 
the  sides  wear  down  and  the  cups  gradually  disap- 
pear. When  the  horse  is  six  years  old  the  cups  in 
the  middle  pair  of  teeth  on  the  lower  jaw  have  disap- 
peared. At  seven  the  cups  are  gone  from  the  second 
pair.  At  eight  the  cups  have  disappeared  from  all 
the  lower  incisors  but  are  still  present  in  the  upper 
jaw.  At  nine  they  are  gone  from  the  upper  middle 
pair,  at  ten  from  the  second  pair,  and  at  eleven  from 
the  third  pair.  After  this  the  shape  and  direction 
of  the  teeth  indicate  something  of  the  age. 

The  horse  walks  on  its  middle  toe,  which  is  large  and 
has  developed  a  horny  covering  called  the  hoof.  The 
rudiments  of  two  other  toes  can  be  seen  at  the  back 
of  the  foot. 

The  joints  about  half  way  up  each  leg  correspond 
to  our  wrist  and  ankle  joints.  The  elbow  and  knee 
joints  are  close  up  to  the  body.  The  round  hoof  of 
the  horse  is  adapted  to  travel  on  dry  plains,  while 
the  split  hoof  of  the  cow  is  adapted  to  wet  marshy 
places.  The  long  leg  is  adapted  for  rapid  travel. 

The  body  is  covered  with  short  hairs  that  lie  close 
to  the  skin.  When  properly  cared  for  they  make  a 
beautiful,  glossy  coat.  The  hair  is  shed  every  year. 
It  is  much  thicker  in  the  winter  than  in  summer. 


DOMESTIC  ANIMALS  305 

Care  of  horses.  One  of  the  first  things  to  consider 
in  caring  for  a  horse  is  its  food.  Make  a  list  of  the 
various  foods  horses  eat.  List  the  kinds  of  hay  used 
in  the  neighborhood.  How  many  feed  timothy  alone? 
Clover  alone?  Timothy  and  cloyer  mixed?  Alfalfa? 
Straw?  Who  feed  oats?  Who  corn?  Compare  these 
foods  as  to  the  amount  of  different  nutrients.  Which 
contain  the  greater  amount  of  roughage?  Grains 
contain  a  high  per  cent  of  carbohydrates  and  not 
much  protein.  Leguminous  hays  contain  proteid  and 
all  hays  roughage.  Since  carbohydrates  produce  fat 
and  heat,  you  can  see  why  foods  containing  carbo- 
hydrates should  be  fed  to  horses  in  greater  quantities 
in  winter  than  in  summer.  Why  do  working  horses 
need  different  kinds  of  food  and  larger  amounts  than 
idle  horses?  When  a  horse  is  working  he  is  using  up 
muscle  just  as  boys  do  when  they  exercise.  There- 
fore a  working  horse  should  be  fed  more  proteid  foods 
because  these  foods  help  to  build  up  muscle.  He  also 
needs  carbohydrate  and  fats  to  supply  energy.  Like 
most  animals,  the  horse  needs  some  salt,  and  a  small 
amount  should  be  given  him  at  least  every  two  weeks. 

Balanced  rations  have  been  arranged  for  horses  as 
well  as  for  cattle.  A  1,200  pound  horse  at  heavy  work 
requires  2.16  pounds  of  proteid,  14.4  pounds  of  carbo- 
hydrates, and  .6  pounds  of  fat.  On  this  basis  the 
following  rations  have  been  worked  out: 


306  STUDIES  IN  SCIENCE 

No.  1  Pro.  C.  H.  Fat. 

Oats,  18  pounds   1.65  8.46  .75 

Timothy  hay,  14  pounds 39  6.08  .19 

No.  2 

Corn,  15  pounds  1.18  10.00  .64 

Clover  hay,  14  pounds 95  5.02  .24 

By  adding  the  columns  you  find  that  each  ration 
approximates  the  amount  required.  The  farmer 
should  use  the  ration  that  is  most  economical  for  him. 

It  is  of  great  importance  to  observe  regularity  in 
the  feeding  of  horses.  Horses  more  than  any  other 
domestic  animals  seem  to  like  order  and  regularity. 
They  seem  to  watch  and  know  when  feeding  time  has 
arrived  and  become  nervous  if  they  are  not  fed.  The 
horse  should  receive  its  heavy  meal  at  night  after 
the  day's  work  is  done.  There  is  a  good  reason  for 
this.  The  stomach  of  the  horse  is  small  compared 
with  that  of  other  large  animals;  hence  when  horses 
are  fed  in  the  evening  they  have  plenty  of  time  to 
chew  and  digest  their  food.  A  good  rule  to  follow 
for  a  working  horse  is  to  feed  one-fourth  the  daily 
ration  in  the  morning  one  hour  before  going  to  work, 
one-fourth  at  noon,  and  one-half  in  the  evening. 

The  same  care  should  be  exercised  in  watering 
horses  as  in  feeding  them.  Most  experts  agree  that 
horses  should  be  watered  before  meals  rather  than 
afterwards,  the  only  exception  being,  perhaps,  with 
the  morning  meal.  Great  care  should  be  taken  to 


DOMESTIC  ANIMALS  307 

avoid  watering  horses  when  they  are  very  warm. 
A  good  horse  may  be  ruined,  sometimes  killed,  by 
drinking  a  large  quantity  of  water  when  in  a  heated 
condition. 

Horses  should  be  housed  in  comfortable,  well-aired 
barns.  They  should  be  kept  clean  by  currying  and 
rubbing  twice  a  day,  and  the  legs  should  receive 
special  attention.  A  rubbing  down  is  quite  necessary 
in  the  evening  after  the  day's  work.  The  horse  will 
rest  much  better  and  be  in  better  condition  for  work 
the  next  day.  During  cold  weather  horses  should  be 
blanketed  when  standing  still,  especially  when  they 
have  traveled  some  distance  and  are  warm  and  per- 
spiring. 

The  harness.  Harness  has  two  uses;  one  is  to 
enable  the  horse  to  do  its  work,  the  other  is  to  enable 
the  driver  to  control  the  horse.  Name  all  the  parts 
of  the  harness  you  know.  What  parts  help  the  horse 
in  pulling  a  load?  What  parts  aid  the  driver  in  con- 
trolling the  horse?  What  parts  of  the  horse  are 
likely  to  be  injured  by  poorly  fitting  harness? 

Discussion.  Since  the  horse  uses  its  shoulders  in 
moving  a  load,  the  collar,  hames,  and  traces  are  the 
parts  that  aid  it  most.  The  bridle,  bit,  and  lines 
enable  the  driver  to  control  and  guide  the  horse. 
Many  horses  suffer  greatly  because  the  harness  does 
not  fit  properly.  A  poorly  fitting  collar  results  in  a 


308  STUDIES  IN  SCIENCE 

sore  neck  or  shoulder.  If  the  bridle  and  bits  are  not 
right  a  sore  mouth  will  result.  An  improperly  fitting 
crupper  may  result  in  a  sore  tail.  A  riding  horse 
should  have  a  saddle  that  fits  properly. 

Harness  should  be  thoroughly  cleaned  and  oiled 
to  prevent  its  becoming  hard  and  stiff. 

Training  horses.  Bad  habits  in  horses  are  usually 
due  to  improper  training.  It  should  always  be  re- 
membered that  horses  rarely  forget  a  trick  or  any- 
thing that  they  have  once  experienced.  If  they  become 
frightened  at  a  piece  of  paper  in  the  road  and  run 
away  they  are  very  likely  to  be  frightened  the  next 
time  they  see  a  piece  of  paper.  Thus  it  is  very  impor- 
tant that  horses  should  be  trained  carefully  so  that 
they  may  have  nothing  to  remember  that  will  later 
be  injurious  either  to  themselves  or  to  their  owners. 

In  breaking  a  horse  one  should  be  firm  yet  kind  and 
gentle.  Horses  should  be  trained  to  stand  still  while 
being  harnessed,  to  stop  promptly  at  the  word 
"whoa,"  and  to  move  backward  at  the  word  "back." 
A  horse  properly  trained  will  not  start  forward  until 
he  is  given  the  word  or  signal  to  start.  Have  you 
not  seen  horses  that  began  to  move  the  moment  the 
driver  took  the  lines  in  his  hand,  instead  of  waiting 
to  be  told  to  go?  Every  farm  boy  should  learn  how 
to  manage  a  horse  and  do  it  in  the  right  way. 

History.     Horses  have  been  known  since  the  begin- 


DOMESTIC  ANIMALS  309 

ning  of  history.  Our  ancestors  in  prehistoric  times 
tamed  wild  horses  and  used  them  in  hunting  other 
animals  that  ran  rapidly.  The  horse  is  one  of  the 
fleetest  runners  known  among  animals. 

The  horse  was  brought  to  America  from  Europe. 
In  Europe  there  are  two  distinct  types  of  horses: 
a  heavy  horse  that  was  found  in  England  in  the 
western  part  of  the  continent,  and  the  Arabian  horse 
that  was  brought  into  Europe  at  the  time  of  the 
Crusades.  The  wild  horses  that  we  read  about  in 
America  were  horses  that  escaped  from  the  early 
Spanish  explorers  and  roamed  over  the  prairies  until 
they  became  wild. 

Colt  project.  Any  boy  or  girl  who  is  interested 
may  with  profit  undertake  a  colt  raising  project 
similar  to  the  calf  project.  Eecords  should  be  kept 
of  the  cost,  the  management,  and  the  condition  of  the 
colt  at  the  beginning  and  the  end  of  the  peirod. 


3.     SWINE 

Material.  Hogs  of  the  neighborhood,  pictures  of 
mature  and  young  pigs. 

Study  a  hog.  Note  the  shape  of  the  body,  the 
length  and  size  of  the  legs,  the  body  covering.  How 
does  the  hair  compare  in  thickness  with  that  of  a 
cow?  Examine  the  feet.  Find  the  number  of  toes. 


310  STUDIES  IN  SCIENCE 

Decide  on  what  part  of  the  foot  the  pig  walks.  Has 
the  divided  hoof  any  advantage  for  the  hog?  Are 
the  rear  toes  of  any  use?  What  is  the  shape  of  the 
face?  Describe  the  ears,  eyes  and  nose.  Look  espe- 
cially at  the  end  of  the  nose.  Note  the  position  of 
the  mouth. 

Make  a  list  of  the  different  kinds  of  food  that  pigs 
eat.  Describe  their  habits  of  feeding.  How  does  the 
nose  aid  in  obtaining  food?  Determine  whether  or 
not  all  the  different  classes  of  teeth  are  present. 
Describe  the  habits  of  pigs  with  reference  to  mud 
and  water. 

How  many  different  breeds  of  hogs  are  represented 
in  your  district?  How  do  they  differ  in  shape,  size, 
color,  etc.  ?  What  is  the  greatest  number  of  hogs 
kept  by  any  one  farmer?  For  what  purpose  are  they 
kept  ?  At  what ,  age  are  hogs  usually  marketed  ? 
What  is  fed  to  hogs  that  are  being  fattened  for 
market  ? 

Discussion.  Hogs  or  swine  have  been  domesticated 
since  a  very  early  time.  Their  origin  is  not  definitely 
known.  It  is  believed,  however,  that  they  were  first 
domesticated  in  Asia  and  are  descendents  of  the  wild 
boar.  (Note  that  the  term  boar  originally  had  the  same 
meaning  as  our  word  hog.)  It  is  also  probable  that 
later  the  wild  swine  of  Europe  was  domesticated  in 
that  country.  Wild  hogs  are  still  found  in  some  parts 


DOMESTIC  ANIMALS  311 

of  Europe  and  Asia,  and  in  some  of  our  southern  and 
southwestern  states.  These  latter  are  not  native  to 
America,  but  are  the  descendants  of  the  domestic 
hogs  that  were  brought  over  here  by  the  early  Span- 
ish explorers.  These  hogs,  like  the  wild  hogs  of 
Europe,  are  thin  and  sharp-nosed.  They  are  com- 
monly known  as  razor  backs.  They  subsist  upon 
herbs,  nuts  of  trees,  roots,  and  insects  found  in  the 
soil. 

The  body  of  the  hog,  as  compared  to  the  height,  is 
long  and  deep.  The  legs  are  short  and  each  foot 
has  four  toes.  The  two  front  toes  are  large  and  it  is 
upon  these  that  the  hog  walks.  The  hind  toes  are 
small  and  placed  higher  up  than  the  front  ones.  They 
are  of  no  use  when  the  hog  walks  on  dry  land,  but 
when  it  walks  on  low,  marshy  ground  these  hind  toes 
help  to  keep  it  from  sinking  into  the  soft  earth. 

The  body  is  covered  rather  scantily  with  very 
stiff  hairs  called  bristles.  They  are  '  strongest  and 
stiffest  along  the  back.  Under  the  bristles  is  a  thick 
leathery  skin.  On  most  hogs  the  hairs  are  so  scat- 
tered that  the  skin  shows  through  plainly  over  the 
entire  body. 

The  bristles  of  the  hog  are  used  in  the  making  of 
brushes.  Shoemakers  use  them  in  making  wax-ends 
with  which  they  sew  shoes. 

The  general  shape  of  the  head  of  the  hog  is  tri- 


312  STUDIES  IN  SCIENCE 

angular,  the  forehead  curving  inward  and  the  cheeks 
outward,  more  or  less  according  to  the  breed.  The  ears 
are  of  interest  because  of  their  large  size.  In  some 
breeds  they  stand  up,  while  in  others  they  droop. 
This  characteristic  aids  in  distinguishing  breeds. 
The  eyes,  though  small,  have  a  keen  vision.  The  nose 
is  one  of  the  pig's  most  interesting  features.  It  ends 
in  a  fleshy  disk,  often  called  the  snout.  This  is 
exceedingly  sensitive  so  that  it  can  detect  the  solid 
grains  of  oats  or  wheat  in  a  pile  of  chaff.  It  is  also 
so  strong  the  hog  can  turn  over  sod  or  dig  down  into 
the  soil  from  six  inches  to  two  feet.  In  order  to 
keep  hogs  from  killing  out  pasture  in  which  they 
feed,  rings  are  put  into  their  snouts  to  keep  them 
from  -" rooting."  The  sense  of  smell  is  very  well 
developed.  Hogs  are  said  to  be  able  to  follow  scent 
quite  as  well  as  a  dog.  The  mouth  opens  under  the 
snout.  All  the  different  kinds  of  teeth  are  present. 
There  are  six  incisors,  two  canines  and  seven  molars 
on  each  jaw.  The  canine  teeth  in  the  upper  jaw  turn 
upward.  In  the  males  these  teeth  grow  quite  long 
and  are  called  tusks.  In  the  wild  boar  the  tusks  are 
very  large  and  are  strong  weapons  of  defense. 

Hogs  have  formed  the  habit  of  wallowing  in  mud 
and  water  for  two  reasons.  One  is  that  they  do  not 
perspire  as  some  other  animals  do,  and  to  keep  cool 
they  lie  down  in  water  and  mud.  The  other  reason 


DOMESTIC  ANIMALS 


313 


if; 


is  that  the  hair  on  their  bodies  is  so  scattered  that 
flies  and  other  insects  have  easy  access  to  the  skin. 
They  get  into  the  mud  and  water  to  protect  themselves 
from  insect  pests. 

Breeds  of  hogs.  There  are  a  number  of  different 
breeds  in  the  United  States,  most  of  which  have  been 
developed  here.  The  favorite  black  breeds  are  the 
Berkshire  and  the  Poland-China,  Both  are  black  with 
white  spots  or  bands 
over  the  body.  The 
Berkshire  has  erect 
ears,  while  those  of 
the  Poland- China  are 
drooping.  They  are 
both  rapid  growers. 

The      most      favored        FiS-  62-    Poland  China,  a  lard  type 

of  hog. 

white  breed  is  known 

as  the  Chester  White.  Hogs  of  this  breed  are  some- 
what slow  maturing  but  are  hardy. 

The  Duroc-Jersey  is  of  a  reddish  brown  color.  It 
has  a  large  frame  and  is  easily  raised.  It  is  becom- 
ing a  great  favorite  in  many  parts  of  the  Middle 
West. 

All  of  the  breeds  named  thus  far  belong  to  the 
lard  or  fat  type.  There  is  another  class  of  hogs 
known  as  the  bacon  type. 

The  fat  hog  has  a  thick,  deep  body,  strong  hams, 


314 


STUDIES  IN  SCIENCE 


short  head,  and  short  legs.  The  bacon  hog  is  not 
as  broad  as  the  fat  hog,  and  has  longer  sides,  lighter 
hams,  and  longer  legs.  Throughout  the  corn  belt  the 
fat  type  is  raised  almost  exclusively.  Farther  north 
some  of  the  bacon  types  are  raised.  In  some  parts 
of  the  East  and  in  Canada  the  bacon  type  is  more 


Fig.  63.     Large  Yorkshire,  a  bacon  type  of  hog. 

common  than .  the  fat  hog.  Among  the  best  known 
bacon  hogs  are  the  Essex,  the  Hampshire  and  the 
Tamworths. 

Care  of  hogs.  How  are  hogs  cared  for  in  your 
neighborhood?  How  are  they  housed?  Describe  any 
hog  houses  that  you  have  seen. 


DOMESTIC  ANIMALS  315 

Farmers  are  everywhere  giving  more  attention  to 
the  care  of  their  hogs.  Formerly  any  place  was 
thought  good  enough  for  these  animals.  Now,  good 
houses  that  will  admit  plenty  of  sunshine  and  air 
are  finding  favor.  These  houses  are  constructed  so 
that  the  hogs  may  have  a  warm,  dry  shelter  during  the 
winter  and  cool  spring  months.  The  most  approved 
houses  are  long  buildings  facing  the  south,  and 
divided  into  pens  from  five  to  eight  feet  wide  and 


Fig.  64.     A  good  hog  house. 

from  eight  to  twelve  feet  long.  From  each  pen  there 
is  a  door  leading  to  an  outside  run.  The  floors  are 
usually  cement,  although  some  are  of  wood.  Troughs 
for  semi-liquid  food  and  for  water  are  placed  along 
the  sides  of  the  pens. 

Food  for  hogs.  While  pigs  are  young  they  should 
be  fed  milk  and  a  little  ground  feed  such  as  shorts. 
Later,  especially  when  they  no  longer  depend  upon 


316  STUDIES  IN  SCIENCE 

their  mother's  milk,  they  should  be  fed  milk  and 
ground  feeds  with  a  little  dry  grain  such  as  oats, 
and  if  possible  they  should  be  allowed  to  run  on 
pasture.  At  this  stage  in  their  lives,  when  they  are 
growing  rapidly,  pasturage  and  other  succulent 
foods  are  excellent  for  them.  When  they  are  from 
six  to  seven  months  old  they  are  ready  to  fatten. 
They  should  now  be  fed  much  more  corn  and  should 
no  longer  be  allowed  to  run  in  the  pasture.  Some 
tests  show  that  alfalfa  fed  with  corn  gives  excellent 
results. 

Diseases.  Hogs,  more  than  any  other  domestic 
animals,  are  subject  to  a  p.umber  of  diseases.  The 
one  most  dreaded  is  cholera.  It  frequently  kills  off 
an  entire  herd  within  a  few  weeks.  This  disease  is 
due  to  bacteria  and  is  very  contagious.  The  bacteria 
may  be  carried  by  animals  that  go  from  one  farm  to 
another  as  dogs,  cats,  pigeons  and  other  birds  that 
feed  in  the  hog  lot.  Men  may  carry  them  on  their 
shoes  as  they  walk  about  in  soil  and  debris.  When- 
ever cholera  is  in  the  neighborhood,  the  greatest  care 
should  be  taken  to  prevent  its  spreading.  The  most 
effective  means  now  used  to  prevent  the  disease  is 
vaccination.  A  serum  is  injected  into  the  blood  of 
all  well  hogs  which  acts  in  much  the  same  way  that 
anti-toxin  acts  to  prevent  diphtheria.  If  it  is  sue- 


DOMESTIC  ANIMALS  317 

cessful,  the  hogs  are  immune  from  the  disease  for  a 
number  of  months. 

Value  of  hogs.  How  valuable  are  hogs  to  the 
average  farmer?  What  are  they  worth?  What  is  a 
good  average  weight  when  the  hog  is  ready  for 
market? 

When  managed  properly  hogs  bring  excellent 
returns  to  the  farmer.  The  price  varies  from  time 
to  time  as  with  every  other  farm  commodity.  It  is 
usually  quoted  at  so  much  per  hundred  pounds.  It 
has  sometimes  been  as  low  as  four  dollars  per  hun- 
dred, but  often  reaches  six,  eight  and  even  twelve 
dollars.  Recently  hogs  have  sold  on  foot  as  high  as 
twenty  dollars  a  hundred.  A  good  average  weight 
of  fat  hogs  from  seven  to  nine  months  of  age  is  from 
two  hundred  and  fifty  to  two  hundred  and  seventy- 
five  pounds.  Older  hogs  weigh  from  three  to  five  hun- 
dred pounds. 

Booklets  and  charts.  Make  a  collection  of  pictures 
showing  different  breeds  of  hogs,  hog  houses,  hog 
cots,  etc.  Paste  these  on  sheets  of  heavy  paper  and 
label  carefully. 

Project.  No  other  farm  animal  lends  itself  so 
readily  to  boys'  and  girls '  projects  as  a  pig.  Procure 
a  pig  a  few  months  old.  Feed  it  till  ready  for  market. 
Keep  a  record  of  feed,  other  expenses,  weight  gained, 
and  profits. 


318  STUDIES  IN  SCIENCE 

j, 

4.     SHEEP 

Material.  Sheep  of  the  neighborhood.  A  portion 
of  a  fleece.  Pictures  of  sheep. 

The  sheep  as  a  type  of  animal.  Make  a  study  of 
a  sheep.  Note  all  the  parts  and  describe  each.  If  you 
do  not  have  access  to  a  living  sheep  procure  some 
good  pictures  and  study  those.*  Note  the  shape  of 
the  body,  the  length  of  the  legs,  the  thickness  of  the 
legs,  the  position  and  manner  of  holding  the  ears, 
the  shape  and  color  of  the  nose,  and  the  size  and 
appearance  of  the  eye.  Study  the  woolly  coat,  its 
color,  thickness,  difference  between  outer  and  inner 
portions,  variations  on  different  parts  of  the  body. 

Note  the  difference  in  appearance  between  the  male 
and  female  sheep.  The  males  are  known  as  rams, 
the  female  are  ewes. 

Study  a  lamb  comparing  with  the  adult. 

What  do  sheep  eat!  "What  other  domestic  animals 
do  they  resemble  in  their  habits  of  eating! 

How  many  farmers  in  your  community  keep  sheep! 
What  different  breeds  are  represented!  For  what 
purpose  are  they  raised!  How  old  are  the  sheep 
when  marketed  for  mutton !  At  what  season  are 
sheep  sheared!  How  is  it  done!  What  is  done  with 
the  wool!  How  much  wool  will  one  sheep  produce 
at  one  shearing! 

*Look  in  a  large  dictionary  for  pictures  of  types  of  sheep. 


DOMESTIC  ANIMALS  319 

History.  Sheep  are  among  the  oldest  domes- 
tic animals.  As  far  back  as  we  can  go  in  written 
history  we  find  sheep  mentioned.  The  exact  origin 
of  our  domestic  sheep  is  not  definitely  known. 
It  is  thought  that  they  originated  from  wild  sheep 
of  Asia  and  Europe.  Some  believe  that  the  European 
breeds  have  been  developed  largely  from  small  wild 
sheep  which  even  yet  inhabit  the  mountains  of 
Greece,  and  the  islands  of  Crete,  Cypress  and  Cor- 
sica. Our  American  breeds  have  been  introduced 
from  Europe. 

Discussion.  In  their  wild  state  sheep  fed  upon  the 
scant  plant  life  found  in  mountainous  regions.  For 
that  reason  the  domestic  animals  are  able  to  subsist 
where  cattle  and  horses  would  almost  starve.  They 
eat  all  sorts  of  weeds  as  well  as  grain  and  clovers. 
In  the  woods  they  eat  young  trees  and  shrubs  and  all 
kinds  of  undergrowth. 

The  arrangement  of  the  teeth  is  similar  to  that  of 
the  cow.  There  are  eight  incisors  on  the  lower  jaw, 
but  there  are  no  upper  front  teeth.  There  are  six 
back  teeth  or  molars  on  each  half  jaw.  The  small 
sharp  pointed  front  teeth  enable  sheep  to  crop  very 
small  plants  close  to  the  ground. 

In  feeding  habits  sheep  resemble  cattle;  that  is, 
they  eat  rapidly  swallowing  the  food  with  little  chew- 
ing. Later  they  bring  the  food  in  small  lumps  back 


320  STUDIES  IN  SCIENCE 

to  the  mouth  and  chew  it  as  they  lie  in  the  shade 
or  stand  together  resting.  As  in  the  case  of  cattle, 
this  process  is  called  chewing  the  cud. 

Sheep  can  readily  climb  hillsides  and  the  rugged 
surfaces  of  mountainous  regions.  Their  thick  coat 
of  wool  makes  it  possible  for  them  to  live  comfortably 
in  cold  regions  and  in  high  elevations. 

Their  native  homes  probably  account  for  the  well 
developed  muscles  in  the  legs  which  enable  them  to 
jump  over  crags  and  across  ravines.  The  foot  below 
the  ankle  joint  is  small  and  delicate.  It  has  two 
toes  upon  which  the  animal  walks.  If  you  look 
closely  you  find  small,  rudimentary  toes  above  and 
to  the  back  of  the  front  toes.  The  hoofs  are  kept 
oiled  by  a  small  gland  that  lies  between  the  toes. 

If  you  observed  a  lamb  you  noticed  that  its  legs 
are  very  long  compared  to  the  size  of  the  body.  For 
this  reason  a  very  young  lamb  can  walk  almost  as 
far  during  the  day  as  the  older  members  of  the  flock. 
Lambs  are  very  active,  skipping,  jumping,  and  play- 
ing constantly  with  each  other. 

Lambs  have  quite  long  tails  but  these  are  cut  off 
while  the  lambs  are  young.  This  is  to  prevent  burs 
and  filth  from  collecting  on  them  and  producing 
disease. 

Types  of  sheep.  We  have  two  distinct  breeds  of 
sheep ;  those  that  are  raised  chiefly  for  their  wool,  and 


DOMESTIC  ANIMALS  321 

those  that  are  raised  for  their  meat.  They  are  known 
as  the  wool  type  and  mutton  type. 

The  wool  type  is  represented  by  the  following 
breeds:  Merino,  Delaine  Merino  and  Rambouillet. 
Their  bodies  are  angular  and  thin;  the  skin  is  often 
wrinkled  so  as  to  form  folds.  The  build  of  the  body 
gives  a  large  surface  for  the  attachment  of  wool. 
The  wool  itself  is  of  a  superior  quality. 

Sheep  of  the  mutton  type  have  rectangular  bodies 
built  somewhat  on  the  plan  of  beef  cattle,  so  that 
they  produce  a  large  amount  of  mutton.  They  are 
divided  into  two  classes,  those  that  have  wool  of 
medium  length  and  those  that  have  long  wool.  The 
most  common  of  the  former  are  the  Southdown, 
Oxford  and  Dorset;  of  the  latter,  Cotswold,  Leicester, 
and  Lincolns. 

Care  of  sheep.  Of  all  domestic  animals  sheep  are 
the  most  easily  cared  for.  Their  feeding  habits  enable 
them  to  clean  up  fields  where  other  animals  can  no 
longer  find  sufficient  food.  They  thrive  best  on  a 
mixture  of  hay,  oats,  some  corn  and  silage.  If  they 
are  being  fattened  for  market  they  are  fed  more  grain 
and  less  roughage.  Lambs  may  be  ready  to  put  on 
the  market  at  from  seven  to  twelve  months  of  age. 

Some  sheep  raisers  make  quite  a  profit  by  fattening 
young  lambs  and  selling  them  at  from  six  to  ten 


322  STUDIES  IN  SCIENCE 

weeks  old.    Their  meat  is  considered  very  choice  and 
brings  a  high  price. 

Because  of  the  warm  coat,  sheep  require  less  shelter 
than  other  animals  during  the  winter.  An  open  shed 
may  be  used.  It  is  quite  essential,  however,  that  it 
be  kept  perfectly  dry. 

Sheep  that  are  kept  for  producing  wool  are  sheared 
in  the  spring.  A  good  Merino  fleece  weighs  from 
twelve  to  twenty  pounds.  Some  of  the  mutton  breeds 
do  not  yield  more  than  eight  pounds  of  wool.  The 
wool  of  the  Merinos  is  used  for  the  finest  grade  of 
wool  cloth.  The  mutton  breeds  produce  a  coarser 
wool  and  the  cloth  made  from  this  is  usually  of  a 
rougher  weave. 

A  good  fleece  should  be  thick  and  even  over  the 
whole  body.  It  should  have  a  strong  well-crimped 
fiber  of  bright  appearance,  and  should  contain  enough 
oil  to  preserve  and  keep  the  fiber  strong. 

It  is  said  that  a  farmer  who  knows  how  to  manage 
his  flock  can  make  the  wool  pay  for  the  feed,  leaving 
the  lambs  raised  as  clear  profit.  Lambs  are  usually 
sold  in  the  fall  so  they  will  not  have  to  be  sheltered 
and  fed  over  winter. 

Wool.  Study  a  piece  of  wool  taken  from  a  sheep. 
How  does  it  differ  from  hair?  If  possible  examine  it 
with  a  hand  lens.  How  does  wool  cloth  feel?  Com- 
pare with  cotton  and  silk. 


DOMESTIC  ANIMALS  321 

those  that  are  raised  for  their  meat.  They  are  known 
as  the  wool  type  and  mutton  type. 

The  wool  type  is  represented  by  the  following 
breeds:  Merino,  Delaine  Merino  and  Rambouillet. 
Their  bodies  are  angular  and  thin;  the  skin  is  often 
wrinkled  so  as  to  form  folds.  The  build  of  the  body 
gives  a  large  surface  for  the  attachment  of  wool. 
The  wool  itself  is  of  a  superior  quality.  .. 

Sheep  of  the  mutton  type  have  rectangular  bodies 
built  somewhat  on  the  plan  of  beef  cattle,  so  that 
they  produce  a  large  amount  of  mutton.  They  are 
divided  into  two  classes,  those  that  have  wool  of 
medium  length  and  those  that  have  long  wool.  The 
most  common  of  the  former  are  the  Southdown, 
Oxford  and  Dorset;  of  the  latter,  Cotswold,  Leicester, 
and  Lincolns. 

Care  of  sheep.  Of  all  domestic  animals  sheep  are 
the  most  easily  cared  for.  Their  feeding  habits  enable 
them  to  clean  up  fields  where  other  animals  can  no 
longer  find  sufficient  food.  They  thrive  best  on  a 
mixture  of  hay,  oats,  some  corn  and  silage.  If  they 
are  being  fattened  for  market  they  are  fed  more  grain 
and  less  roughage.  Lambs  may  be  ready  to  put  on 
the  market  at  from  seven  to  twelve  months  of  age. 

Some  sheep  raisers  make  quite  a  profit  by  fattening 
young  lambs  and  selling  them  at  from  six  to  ten 


322  STUDIES  IN  SCIENCE 

weeks  old.    Their  meat  is  considered  very  choice  and 
brings  a  high  price. 

Because  of  the  warm  coat,  sheep  require  less  shelter 
than  other  animals  during  the  winter.  An  open  shed 
may  be  used.  It  is  quite  essential,  however,  that  it 
be  kept  perfectly  dry. 

Sheep  that  are  kept  for  producing  wool  are  sheared 
in  the  spring.  A  good  Merino  fleece  weighs  from 
twelve  to  twenty  pounds.  Some  of  the  mutton  breeds 
do  not  yield  more  than  eight  pounds  of  wool.  The 
wool  of  the  Merinos  is  used  for  the  finest  grade  of 
wool  cloth.  The  mutton  breeds  produce  a  coarser 
wool  and  the  cloth  made  from  this  is  usually  of  a 
rougher  weave. 

A  good  fleece  should  be  thick  and  even  over  the 
whole  body.  It  should  have  a  strong  well-crimped 
fiber  of  bright  appearance,  and  should  contain  enough 
oil  to  preserve  and  keep  the  fiber  strong. 

It  is  said  that  a  farmer  who  knows  how  to  manage 
his  flock  can  make  the  wool  pay  for  the  feed,  leaving 
the  lambs  raised  as  clear  profit.  Lambs  are  usually 
sold  in  the  fall  so  they  will  not  have  to  be  sheltered 
and  fed  over  winter. 

Wool.  Study  a  piece  of  wool  taken  from  a  sheep. 
How  does  it  differ  from  hair!  If  possible  examine  it 
with  a  hand  lens.  How  does  wool  cloth  feel?  Com- 
pare with  cotton  and  silk. 


DOMESTIC  ANIMALS  323 

Wool  fibers  have  little  scales  or  projections  along 
the  sides,  while  a  hair  is  smooth.  These  scales  make 
wool  feel  rough  against  the  skin. 

Make  a  list  of  all  the  things  you  know  that  are 
made  of  wool. 

Sheep  industry.  Sheep  raising  is  not  as  great  an 
industry  in  United  States  as  that  of  swine.  Farmers 
are  beginning  to  realize,  however,  that  a  flock  of  sheep 
on  the  farm  is  a  paying  investment.  The  eastern 
states  and  those  of  the  Middle  West  for  the  most  part 
raise  the  mutton  types.  In  the  far  West  more 
Merino  sheep  are  raised.  Here  are  great  ranches 
where  several  thousands  of  sheep  may  be  found  in 
one  flock.  In  the  Summer  the  herders  with  their 
faithful  shepherd  dogs  take  the  flocks  to  the  moun- 
tains and  hillsides  where  they  feed  upon  the  scant 
vegetation.  In  the  winter  they  are  brought  down 
to  the  valley  where  they  are  sheltered  and  fed. 

Projects.  The  raising  of  lambs  either  for  meat  or 
wool  production  is  a  project  well  worth  undertaking 
by  any  boy  or  girl  who  lives  in  a  region  where  sheep 
are  raised. 

Choose  for  the  project  one  or  more  spring  lambs 
and  care  for  them  until  ready  to  market  for  mutton, 
which  will  be  from  six  to  eight  months.  Keep  a 
record  of  expenses;  cost  of  feed,  labor,  receipts,  and 
profits. 


324  STUDIES  IN  SCIENCE 

Instead  of  selling  the  sheep  for  mutton  you  may 
keep  them  for  their  wool  and  to  produce  lambs. 

Keep  a  record  of  your  expenses,  receipts  and 
profits.  Take  into  account  the  value  of  the  sheep  and 
lambs  produced. 


DOMESTIC  ANIMALS  323 

Wool  fibers  have  little  scales  or  projections  along 
the  sides,  while  a  hair  is  smooth.  These  scales  make 
wool  feel  rough  against  the  skin. 

Make  a  list  of  all  the  things  you  know  that  are 
made  of  wool. 

Sheep  industry.  Sheep  raising  is  not  as  great  an 
industry  in  United  States  as  that  of  swine.  Farmers 
are  beginning  to  realize,  however,  that  a  flock  of  sheep 
on  the  farm  is  a  paying  investment.  The  eastern 
stages  and  those  of  the  Middle  West  for  the  most  part 
raise  the  mutton  types.  In  the  far  West  more 
Merino  sheep  are  raised.  Here  are  great  ranches 
where  several  thousands  of  sheep  may  be  found  in 
one  flock.  In  the  summer  the  herders  with  their 
faithful  shepherd  dogs  take  the  flocks  to  the  moun- 
tains and  hillsides  where  they  feed  upon  the  scant 
vegetation.  In  the  winter  they  are  brought  down 
to  the  valley  where  they  are  sheltered  and  fed. 

Projects.  The  raising  of  lambs  either  for  meat  or 
wool  production  is  a  project  well  worth  undertaking 
by  any  boy  or  girl  who  lives  in  a  region  where  sheep 
are  raised. 

Choose  for  the  project  one  or  more  spring  lambs 
and  care  for  them  until  ready  to  market  for  mutton, 
which  will  be  from  six  to  eight  months.  Keep  a 
record  of  expenses;  cost  of  feed,  labor,  receipts,  and 
profits. 


324  STUDIES  IN  SCIENCE 

Instead  of  selling  the  sheep  for  mutton  you  may 
keep  them  for  their  wool  and  to  produce  lambs. 

Keep  a  record  of  your  expenses,  receipts  and 
profits.  Take  into  account  the  value  of  the  sheep  and 
lambs  produced. 


WINTER  STUDIES 

CHAPTER  XIX 

LIGHT  AND  LIGHTING 

Materials.  An  ordinary  candle,  several  small 
Christmas  candles,  kerosene  lamp,  gas  fixture,  elec- 
tric light  bulb,  test  tube,  rubber  stopper,  glass  tube, 
small  pieces  of  soft  coal. 

Study.  What  method  of  artificial  lighting  is  used 
in  your  home?  In  your  school  building ?  Make  a  list 
of  all  the  different  methods  of  lighting  that  you  know. 
Group  them  into  two  classes:  1.  Those  in  which  the 
light  is  directly  produced  by  a  flame.  2.  Those  that 
produce  light  in  some  other  way. 

The  candle.  Study  a  candle  that  has  not  been 
used.  Of  what  is  it  made!  Examine  the  wick  and 
describe  it.  What  is  the  shape  of  the  candle  at  the 
top?  At  the  bottom?  How  was  it  made?  Light  a 
small  piece  of  candle.  Watch  very  carefully  to  see 
what  happens  till  the  flame  remains  steady.  After 
it  has  burned  a  short  time  notice  the  top  of  the  candle. 
What  is  in  the  hollow  cup?  What  forms  the  sides 
of  the  cup?  How  close  to  the  cup  does  the  flame 

325 


326  STUDIES  IN  SCIENCE 

extend!  How  high  is  the  flame!  Describe  its  shape. 
Where  is  it  widest!  Where  narrowest!  What  dif- 
ferent colors  do  you  see  in  it!  How  does  it  look  at 
the  center!  Make  a  drawing  to  show  all  the  parts  you 
have  observed. 

Experiment.    What  produces  the  candle  flame! 

When  your  candle  has  been  burning  for  some  min- 
utes blow  out  the  flame.  What  do  you  see  coming 
from  the  end  of  the  wick!  What  color  is  the  smoke! 
What  do  you  think  this  smoke  is!  Examine  the 
warm  wick  and  determine  what  is  in  it.  Explain  the 
relation  between  the  melted  paraffin  in  the  wick  and 
the  smoke  or  vapor  coming  from  it. 

Relight  the  candle  and  allow  it  to  burn  for  a  minute 
or  two,  then  blow  out  the  flame.  Have  a  lighted 
match  ready  and  the  moment  the  flame  is  out  apply 
the  match  to  the  smoke.  Describe  what  happens. 
Try  this  again  and  again  till  you  make  up  your  mind 
what  it  is  that  really  burns  and  makes  the  flame. 

Experiment.  Will  liquid  paraffin  burn!  If  you 
are  not  quite  certain  whether  it  is  the  melted  paraffin 
or  the  vapor  of  paraffin  that  burns,  make  this  experi- 
ment. Melt  a  little  paraffin  in  a  tin  cup  or  deep 
spoon.  Apply  a  lighted  match  to  see  if  it  will  burn. 
How  many  different  forms  of  paraffin  are  present  in 
the  burning  candle!  What  besides  the  paraffin  vapor 
is  needed  to  make  the  candle  flame! 


WINTER  STUDIES 

CHAPTER  XIX 

LIGHT  AND  LIGHTING 

Materials.  An  ordinary  candle,  several  small 
Christmas  candles,  kerosene  lamp,  gas  fixture,  elec- 
tric light  bulb,  test  tube,  rubber  stopper,  glass  tube, 
small  pieces  of  soft  coal. 

Study.  What  method  of  artificial  lighting  is  used 
in  your  home?  In  your  school  building?  Make  a  list 
of  all  the  different  methods  of  lighting  that  you  know. 
Group  them  into  two  classes:  1.  Those  in  which  the 
light  is  directly  produced  by  a  flame.  2.  Those  that 
produce  light  in  some  other  way. 

The  candle.  Study  a  candle  that  has  not  been 
used.  Of  what  is  it  made?  Examine  the  wick  and 
describe  it.  What  is  the  shape  of  the  candle  at  the 
top?  At  the  bottom?  How  was  it  made?  Light  a 
small  piece  of  candle.  Watch  very  carefully  to  see 
what  happens  till  the  flame  remains  steady.  After 
it  has  burned  a  short  time  notice  the  top  of  the  candle. 
What  is  in  the  hollow  cup?  What  forms  the  sides 
of  the  cup?  How  close  to  the  cup  does  the  flame 

325 


326  STUDIES  IN  SCIENCE 

extend?  How  high  is  the  flame?  Describe  its  shape. 
Where  is  it  widest!  Where  narrowest?  What  dif- 
ferent colors  do  you  see  in  it?  How  does  it  look  at 
the  center?  Make  a  drawing  to  show  all  the  parts  you 
have  observed. 

Experiment.    What  produces  the  candle  flame? 

When  your  candle  has  been  burning  for  some  min- 
utes blow  out  the  flame.  What  do  you  see  coming 
from  the  end  of  the  wick?  What  color  is  the  smoke? 
What  do  you  think  this  smoke  is?  Examine  the 
warm  wick  and  determine  what  is  in  it.  Explain  the 
relation  between  the  melted  paraffin  in  the  wick  and 
the  smoke  or  vapor  coming  from  it. 

Eelight  the  candle  and  allow  it  to  burn  for  a  minute 
or  two,  then  blow  out  the  flame.  Have  a  lighted 
match  ready  and  the  moment  the  flame  is  out  apply 
the  match  to  the  smoke.  Describe  what  happens. 
Try  this  again  and  again  till  you  make  up  your  mind 
what  it  is  that  really  burns  and  makes  the  flame. 

Experiment.  Will  liquid  paraffin  burn?  If  you 
are  not  quite  certain  whether  it  is  the  melted  paraffin 
or  the  vapor  of  paraffin  that  burns,  make  this  experi- 
ment. Melt  a  little  paraffin  in  a  tin  cup  or  deep 
spoon.  Apply  a  lighted  match  to  see  if  it  will  burn. 
How  many  different  forms  of  paraffin  are  present  in 
the  burning  candle?  What  besides  the  paraffin  vapor 
is  needed  to  make  the  candle  flame? 


LIGHT  AND  LIGHTING  327 

Explanation.  When  you  lit  the  candle  the  heat 
of  the  match  melted  the  paraffin  or  tallow  in  the 
upper  part  of  the  wick  and  a  small  part  of  the  liquid 
changed  to  vapor  and  began  to  burn.  The  heat  from 
this  melted  more  paraffin  and  more  vapor  was  formed. 
Presently  there  was  sufficient  heat  to  melt  the  paraffin 
around  the  wick  and  form  a  cup  at  the  top  of  the 
candle.  The  liquid  paraffin  was  absorbed  by  the 
wick,  was  changed  to  vapor  at  the  top  and  burned. 
This  explains  why  the  flame  is  small  at  first  but 
gradually  increases  in  size  till  there  is  a  steady  sup- 
ply of  vapor  at  the  top  of  the  wick. 

You  noticed  that  the  burning  seems  to  take  place 
along  the  outer  portion  of  the  flame.  The  inner  dark 
portion  is  the  paraffin  vapor  or  gas  that  is  not  burning. 
You  have  already  discovered  that  air  is  necessary 
for  burning  to  take  place,  so  it  is  easy  to  see  why  the 
burning  is  at  the  outer  portion  where  there  is  a  con- 
stant supply  of  fresh  air. 

Experiment.  What  is  meant  by  candle  power? 
Darken  the  room  as  much  as  possible.  Light  an  ordi- 
nary candle  and  place  it  on  a  table.  On  the  same 
table  about  two  feet  from  the  first  candle  place  a 
lighted  Christmas  candle.  When  both  are  burning 
brightly  open  a  book  on  the  table  about  half  way 
between  the  two  lights,  and  begin  to  read.  When  you 
have  read  about  a  minute  have  some  one  extinguish 


328  STUDIES  IN  SCIENCE 

the  flame  of  the  larger  candle.  Continue  to  read. 
Have  the  person  relight  the  larger  candle  and  after 
a  few  moments  extinguish  the  flame  of  the  small 
one.  What  difference  do  you  notice  as  to  the  strength 
of  the  light  from  the  two  candles? 

Candle  power.  You  often  hear  people  speak  of  the 
candle  power  of  different  kinds  of  light.  The  electric 
lights  used  in  our  homes  are  commonly  8  or  16  candle 
power.  A  standard  candle  is  used  to  measure  the 
intensity  of  light.  Your  simple  experiment  with  the 
two  candles  proved  that  there  is  a  great  difference 
in  the  intensity  of  light  given  out  by  different  lighted 
bodies.  Scientists  by  careful  measurements  decided 
on  a  standard  with  which  to  measure  the  illuminating 
power  of  artificial  light.  One  candle  power  is  the 
amount  of  light  emitted  by  a  sperm  candle  seven- 
eighths  of  an  inch  in  diameter  and  burning  120  grains 
of  sperm  oil  per  hour. 

Lights  used  in  early  times.  Before  the  candle  came 
into  use,  a  very  crude  form  of  lamp  was  used  for 
lighting.  This  consisted  of  a  vessel  containing  melted 
fat,  into  which  a  piece  of  twisted  cloth  was  thrust 
for  a  wick.  This  primitive  lamp  was  really  the  fore- 
runner of  the  candle.  In  the  early  pioneer  days  of 
our  country,  before  primitive  lamps  and  candles  came 
into  use,  homes  were  lighted  by  pine  knots  or  by  the 
light  which  came  from  the  fireplace. 


LIGHT  AND  LIGHTING  327 

Explanation.  When  you  lit  the  candle  the  heat 
of  the  match  melted  the  paraffin  or  tallow  in  the 
upper  part  of  the  wick  and  a  small  part  of  the  liquid 
changed  to  vapor  and  began  to  burn.  The  heat  from 
this  melted  more  paraffin  and  more  vapor  was  formed. 
Presently  there  was  sufficient  heat  to  melt  the  paraffin 
around  the  wick  and  form  a  cup  at  the  top  of  the 
candle.  The  liquid  paraffin  was  absorbed  by  the 
wick,  was  changed  to  vapor  at  the  top  and  burned. 
This  explains  why  the  flame  is  small  at  first  but 
gradually  increases  in  size  till  there  is  a  steady  sup- 
ply of  vapor  at  the  top  of  the  wick. 

You  noticed  that  the  burning  seems  to  take  place 
along  the  outer  portion  of  the  flame.  The  inner  dark 
portion  is  the  paraffin  vapor  or  gas  that  is  not  burning. 
You  have  already  discovered  that  air  is  necessary 
for  burning  to  take  place,  so  it  is  easy  to  see  why  the 
burning  is  at  the  outer  portion  where  there  is  a  con- 
stant supply  of  fresh  air. 

Experiment.  "What  is  meant  by  candle  power? 
Darken  the  room  as  much  as  possible.  Light  an  ordi- 
nary candle  and  place  it  on  a  table.  On  the  same 
table  about  two  feet  from  the  first  candle  place  a 
lighted  Christmas  candle.  When  both  are  burning 
brightly  open  a  book  on  the  table  about  half  way 
between  the  two  lights,  and  begin  to  read.  When  you 
have  read  about  a  minute  have  some  one  extinguish 


328  STUDIES  IN  SCIENCE 

the  flame  of  the  larger  candle.  Continue  to  read. 
Have  the  person  relight  the  larger  candle  and  after 
a  few  moments  extinguish  the  flame  of  the  small 
one.  What  difference  do  you  notice  as  to  the  strength 
of  the  light  from  the  two  candles! 

Candle  power.  You  often  hear  people  speak  of  the 
candle  power  of  different  kinds  of  light.  The  electric 
lights  used  in  our  homes  are  commonly  8  or  16  candle 
power.  A  standard  candle  is  used  to  measure  the 
intensity  of  light.  Your  simple  experiment  with  the 
two  candles  proved  that  there  is  a  great  difference 
in  the  intensity  of  light  given  out  by  different  lighted 
bodies.  Scientists  by  careful  measurements  decided 
on  a  standard  with  which  to  measure  the  illuminating 
power  of  artificial  light.  One  candle  power  is  the 
amount  of  light  emitted  by  a  sperm  candle  seven- 
eighths  of  an  inch  in  diameter  and  burning  120  grains 
of  sperm  oil  per  hour. 

Lights  used  in  early  times.  Before  the  candle  came 
into  use,  a  very  crude  form  of  lamp  was  used  for 
lighting.  This  consisted  of  a  vessel  containing  melted 
fat,  into  which  a  piece  of  twisted  cloth  was  thrust 
for  a  wick.  This  primitive  lamp  was  really  the  fore- 
runner of  the  candle.  In  the  early  pioneer  days  of 
our  country,  before  primitive  lamps  and  candles  came 
into  use,  homes  were  lighted  by  pine  knots  or  by  the 
light  which  came  from  the  fireplace. 


LIGHT  AND  LIGHTING  329 

At  first  candles  were  made  by  a  process  called 
dipping.  Tallow  was  melted  in  a  large  iron  kettle. 
Strings,  sometimes  as  many  as  a  dozen  at  once,  were 
tied  to  sticks  a  foot  or  two  in  length  and  dipped  into 
the  hot  tallow.  Then  they  were  taken  out,  hung  up 
a  few  minutes  until  the  tallow  hardened,  when  they 
were  dipped  again  for  a  moment.  This  process  was 
repeated  again  and  again  till  the  candles  were  of  the 
necessary  size.  You  can  imagine  how  much  time  was 
required  to  dip  enough  candles  to  last  the  family 
for  a  whole  year. 

After  a  time  candles  were  made  by  molding.  I 
wonder  if  any  of  you  may  have  in  your  home  an  old 
set  of  candle  molds?  The  molds  were  first  strung 
with  the  wicking,  then  the  melted  tallow  was  poured 
in.  The  candles  we  use  today  are  made  in  molds 
but  the  work  is  done  in  factories  instead  of  at  home. 
Most  candles  we  have  today  are  made  of  paraffin 
instead  of  tallow. 

Paraffin  is  made  from  crude  petroleum  or  crude  oil. 
It  melts  at  a  high  temperature.  When  the  candle  is 
burning  the  heat  from  it  melts  the  paraffin  around 
the  wick.  This  is  changed  to  vapor  or  gas  at  the 
top  of  the  wick;  so  you- have  in  a  burning  candle  an 
excellent  example  of  the  three  forms  in  which  matter 
of  any  kind  may  exist;  solid,  liquid,  and  gas. 

The  kerosene  lamp.     Study  a  kerosene  lamp  which 


330  STUDIES  IN  SCIENCE 

is  about  half  full  of  kerosene.  Write  the  names  of 
all  the  parts  and  try  to  determine  the  use  of  each. 
What  is  in  the  bowl?  In  the  upper  part  of  the  wick? 
Light  the  lamp  and  compare  the  flame  with  that  of 
the  candle. 

Experiment.  To  determine  the  use  of  the  chim- 
ney. Light  the  lamp  and  put  the  chimney  in  place. 
Watch  the  flame  to  determine  whether  or  not  it  is 
steady.  Extinguish  the  flame  and  remove  the  chim- 
ney. Eelight  the  lamp.  Try  this  several  times,  in 
a  draft  and  in  quiet  air,  till  you  are  certain  that  the 
chimney  has  a  special  use. 

Experiment.  To  determine  what  burns  to  produce 
the  flame. 

Light  the  lamp  and  do  not  put  on  the  chimney. 
Blow  out  the  flame  as  you  did  in  the  candle  experi- 
ment, and  by  trying  to  light  the  gas  or  smoke  that 
comes  from  the  wick  determine  whether  it  is  the 
liquid  kerosene  or  the  gas  that  burns  and  makes  the 
flame. 

Experiment.  Look  carefully  at  the  burner  to  deter- 
mine whether  any  provision  is  made  for  the  admis- 
sion of  air  to  the  upper  part  of  the  wick.  Trace  the 
air  from  the  outside  into  the  chimney.  To  do  this 
light  a  small  splinter  of  pine  wood,  a  twisted  paper 
lighter,  or  a  piece  of  punk.  Allow  it  to  burn  a  few 
moments,  then  blow  out  the  flame  and  hold  it  below 


LIGHT  AND  LIGHTING  329 


At  first  candles  were  made  by  a  process 
dipping.  Tallow  was  melted  in  a  large  iron  kettle. 
Strings,  sometimes  as  many  as  a  dozen  at  once,  were 
tied  to  sticks  a  foot  or  two  in  length  and  dipped  into 
the  hot  tallow.  Then  they  were  taken  out,  hung  up 
a  few  minutes  until  the  tallow  hardened,  when  they 
were  dipped  again  for  a  moment.  This  process  was 
repeated  again  and  again  till  the  candles  were  of  the 
necessary  size.  You  can  imagine  how  much  time  was 
required  to  dip  enough  candles  to  last  the  family 
for  a  whole  year. 

After  a  time  candles  were  made  by  molding.  I 
wonder  if  any  of  you  may  have  in  your  home  an  old 
set  of  candle  molds?  The  molds  were  first  strung 
with  the  wicking,  then  the  melted  tallow  was  poured 
in.  The  candles  we  use  today  are  made  in  molds 
but  the  work  is  done  in  factories  instead  of  at  home. 
Most  candles  we  have  today  are  made  of  paraffin 
instead  of  tallow. 

Paraffin  is  made  from  crude  petroleum  or  crude  oil. 
It  melts  at  a  high  temperature.  When  the  candle  is 
burning  the  heat  from  it  melts  the  paraffin  around 
the  wick.  This  is  changed  to  vapor  or  gas  at  the 
top  of  the  wick;  so  you  have  in  a  burning  candle  an 
excellent  example  of  the  three  forms  in  which  matter 
of  any  kind  may  exist;  solid,  liquid,  and  gas. 

The  kerosene  lamp.     Study  a  kerosene  lamp  which 


330  STUDIES  IN  SCIENCE 

is  about  half  full  of  kerosene.  Write  the  names  of 
all  the  parts  and  try  to  determine  the  use  of  each. 
What  is  in  the  bowl?  In  the  upper  part  of  the  wick? 
Light  the  lamp  and  compare  the  flame  with  that  of 
the  candle. 

Experiment.  To  determine  the  use  of  the  chim- 
ney. Light  the  lamp  and  put  the  chimney  in  place. 
Watch  the  flame  to  determine  whether  or  not  it  is 
steady.  Extinguish  the  flame  and  remove  the  chim- 
ney. Eelight  the  lamp.  Try  this  several  times,  in 
a  draft  and  in  quiet  air,  till  you  are  certain  that  the 
chimney  has  a  special  use. 

Experiment.  To  determine  what  burns  to  produce 
the  flame. 

Light  the  lamp  and  do  not  put  on  the  chimney. 
Blow  out  the  flame  as  you  did  in  the  candle  experi- 
ment, and  by  trying  to  light  the  gas  or  smoke  that 
comes  from  the  wick  determine  whether  it  is  the 
liquid  kerosene  or  the  gas  that  burns  and  makes  the 
flame. 

Experiment.  Look  carefully  at  the  burner  to  deter- 
mine whether  any  provision  is  made  for  the  admis- 
sion of  air  to  the  upper  part  of  the  wick.  Trace  the 
air  from  the  outside  into  the  chimney.  To  do  this 
light  a  small  splinter  of  pine  wood,  a  twisted  paper 
lighter,  or  a  piece  of  punk.  Allow  it  to  burn  a  few 
moments,  then  blow  out  the  flame  and  hold  it  below 


LIGHT  AND  LIGHTING  331 

the  burner.  Watch  to  see  where  the  smoke  enters  the 
chimney.  Hold  the  smoking  splinter  above  the  chimney 
to  determine  the  direction  of  the  air  currents  there. 
What  causes  the  air  to  move  through  the  base  of  the 
burner  toward  the  flame? 

What  is  kerosene  and  how  is  to  obtained? 

Explanation.  You  probably  have  decided  from 
your  experiments  that  the  chimney  and  burner  to- 
gether regulate  the  amount  of  air  that  is  brought  to 
the  flame.  The  openings  in  the  base  of  the  burner 
allow  the  cool  air  from  below  to  enter  and  the  cap 
directs  the  air  toward  the  flame. 

You  proved  by  experiment  that  it  is  the  gas  or 
vapor  of  kerosene  that  burns  and  not  the  liquid. 
The  fact  is  that  every  flame  in  the  world  is  produced 
by  burning  gas  or  vapor. 

Kerosene  is  another  product  of  petroleum  or  crude 
oil.  Look  in  your  geography  to  find  out  where  the 
great  oil  fields  of  United  States  are  located  and  make 
a  list  of  all  the  uses  of  crude  petroleum.  Perhaps 
you  are  near  enough  to  a  region  where  there  are  oil 
wells  to  visit  them  and  see  how  the  oil  is  obtained. 

Crude  petroleum  is  .a  mixture  of  a  number  of  dif- 
ferent liquids.  To  obtain  these  the  petroleum  is 
heated  and  the  liquids  are  changed  into  vapors.  The 
vapor  is  caught  in  large  vessels  where  it  condenses 
and  changes  back  into  a  liquid.  The  lightest  liquid 


332  STUDIES  IN  SCIENCE 

changes  to  vapor  first  and  is  caught  by  itself.  Gas- 
oline is  lighter  than  kerosene,  so  it  vaporizes  first  and 
is  obtained  before  kerosene. 

The  process  of  separating  a  mixture  of  liquids  by 
vaporization  and  then  condensing  them  is  called 
distillation. 

The  main  products  distilled  from  petroleum  are: 
light  gasoline,  heavy  gasoline,  naphtha,  kerosene, 
vaseline  and  paraffin. 

Gas  lamp.  Study  an  ordinary  gas  lamp  used  for 
lighting  homes.  Write  the  names  of  the  parts. 

Light  the  lamp.  Can  you  see  a  flame!  What  pro- 
duces the  light!  Remove  the  mantle  from  the  burner. 
(This  must  be  done  very  carefully  or  the  mantle  will 
break.)  Now  turn  on  the  gas  and  light  it.  What  is 
the  color  of  the  flame!  Does  it  give  a  good  light! 
Examine  the  lower  part  of  the  tube  which  leads  to 
the  flame  for  air  openings  that  might  admit  air  into 
the  tube.  If  you  have  an  ordinary  gas  jet  that  does 
not  have  a  mantle  or  globe,  light  it.  What  is  the 
color  of  the  flame!  Does  it  have  an  opening  in  the 
tube  to  admit  air!  What  really  happens  when  you 
turn  on  the  gas!  Find  the  gas  pipes  and  meter  in 
the  basement.  What  is  the  meter  for!  Is  the  gas 
that  you  use  manufactured  or  natural !  How  is  manu- 
factured gas  sold! 

Experiment.     To  generate  coal  gas.    Procure  a  test 


LIGHT  AND  LIGHTING  331 

the  burner.  Watch  to  see  where  the  smoke  enters  the 
chimney.  Hold  the  smoking  splinter  above  the  chimney 
to  determine  the  direction  of  the  air  currents  there. 
What  causes  the  air  to  move  through  the  base  of  the 
burner  toward  the  flame? 

What  is  kerosene  and  how  is  to  obtained? 

Explanation.  You  probably  have  decided  from 
your  experiments  that  the  chimney  and  burner  to- 
gether regulate  the  amount  of  air  that  is  brought  to 
the  flame.  The  openings  in  the  base  of  the  burner 
allow  the  cool  air  from  below  to  enter  and  the  cap 
directs  the  air  toward  the  flame. 

You  proved  by  experiment  that  it  is  the  gas  or 
vapor  of  kerosene  that  burns  and  not  the  liquid. 
The  fact  is  that  every  flame  in  the  world  is  produced 
by  burning  gas  or  vapor. 

Kerosene  is  another  product  of  petroleum  or  crude 
oil.  Look  in  your  geography  to  find  out  where  the 
great  oil  fields  of  United  States  are  located  and  make 
a  list  of  all  the  uses  of  crude  petroleum.  Perhaps 
you  are  near  enough  to  a  region  where  there  are  oil 
wells  to  visit  them  and  see  how  the  oil  is  obtained. 

Crude  petroleum  is  a  mixture  of  a  number  of  dif- 
ferent liquids.  To  obtain  these  the  petroleum  is 
heated  and  the  liquids  are  changed  into  vapors.  The 
vapor  is  caught  in  large  vessels  where  it  condenses 
and  changes  back  into  a  liquid.  The  lightest  liquid 


332  STUDIES  IN  SCIENCE 

changes  to  vapor  first, and  is  caught  by  itself.  Gas- 
oline is  lighter  than  kerosene,  so  it  vaporizes  first  and 
is  obtained  before  kerosene. 

The  process  of  separating  a  mixture  of  liquids  by 
vaporization  and  then  condensing  them  is  called 
distillation. 

The  main  products  distilled  from  petroleum  are: 
light  gasoline,  heavy  gasoline,  naphtha,  kerosene, 
vaseline  and  paraffin. 

Gas  lamp.  Study  an  ordinary  gas  lamp  used  for 
lighting  homes.  Write  the  names  of  the  parts. 

Light  the  lamp.  Can  you  see  a  flame?  What  pro- 
duces the  light  ?  Remove  the  mantle  from  the  burner. 
(This  must  be  done  very  carefully  or  the  mantle  will 
break.)  Now  turn  on  the  gas  and  light  it.  What  is 
the  color  of  the  flame!  Does  it  give  a  good  light? 
Examine  the  lower  part  of  the  tube  which  leads  to 
the  flame  for  air  openings  that  might  admit  air  into 
the  tube.  If  you  have  an  ordinary  gas  jet  that  does 
not  have  a  mantle  or  globe,  light  it.  What  is  the 
color  of  the  flame?  Does  it  have  an  opening  in  the 
tube  to  admit  air?  What  really  happens  when  you 
turn  on  the  gas?  Find  the  gas  pipes  and  meter  in 
the  basement.  What  is  the  meter  for?  Is  the  gas 
that  you  use  manufactured  or  natural  ?  How  is  manu- 
factured gas  sold? 

Experiment.     To  generate  coal  gas.    Procure  a  test 


LIGHT  AND  LIGHTING  333 

tube,  a  rubber  stopper  with  a  hole  in  it,  and  a  piece  of 
glass  tubing  about  six  inches  long  that  fits  tight  in 
the  stopper.  Place  a  piece  of  soft  coal  about  the  size 
of  a  hickory  nut  in  the  test  tube.  Put  in  the  rubber 
stopper.  Hold  the  test  tube  almost  horizontally, 
tipped  slightly  downward  at  the  mouth.  With  an 
alcohol  lamp  heat  the  coal.  When  the  vapor  comes 
out  of  the  tube  light  it  and  you  have  a  small  gas  jet. 

Explanation.  Most  gas  lamps  have  a  mantle  which 
conceals  the  flame.  The  flame  is  what  is  known  as  a 
blue  flame.  It  is  veiy  hot  but  not  bright  so  it  gives 
a  very  poor  light.  But  the  mantle  becomes  so  hot 
that  it  glows  with  a  white  heat  and  produces  a  very 
good  light.  With  this  kind  of  a  light  the  air  enters 
at  the  air  openings  on  the  side  of  the  tube.  When 
you  turn  the  gas  on  it  mixes  with  the  air  before  it 
reaches  the  flame.  A  lamp  that  has  the  air  and  gas 
supply  mixed  in  proper  proportions  makes  a  hot 
blue  flame. 

In  the  open  jet  the  air  mixes  with  the  gas  as  it 
burns.  This  produces  a  flame  similar  to  that  of  the 
candle  or  kerosene  lamp.  It  does  not  produce  as  good 
a  light  as  the  lamp  with  the  mantle  and  it  burns  more 
gas. 

Different  kinds  of  gas  are  used  for  lighting  pur- 
poses. Some  people  have  their  own  gas  plants  and 
generate  a  gas  out  of  gasoline.  Others  have  acetylene 


334  STUDIES  IN  SCIENCE 

gas  machines.  In  some  places  natural  gas  that  is 
found  far  down  in  the  earth  is  used.  Wells  are  sunk 
and  the  gas  piped  from  them  to  buildings.  Many 
towns  and  cities  manufacture  gas  from  coal  or  other 
materials  and  pipe  this  to  homes  and  other  buildings. 
It  flows  through  a  meter  in  each  house  and  by  a 
device  the  amount  used  is  measured  in  cubic  feet. 
The  price  of  gas  varies  in  different  places  from  eighty 
cents  to  one  dollar  and  twenty-five  cents  per  1,000 
cubic  feet. 

Electric  lights.  Examine  an  electric  light  bulb. 
What  do  you  find?  Turn  on  the  electricity.  Is  there 
any  flame  in  the  bulb!  What  produces  the  light? 

Experiment.  A  light  without  a  flame.  Put  an  iron 
poker  in  the  stove  or  furnace  and  allow  it  to  remain 
until  it  is  very  hot,  then  take  it  out  and  hold  it, 
heated  end  up,  in  a  dark  room  noting  the  light  that 
it  gives  out.  If  there  were  some  way  that  you  could 
keep  it  white  hot  would  it  light  a  room  fairly  well? 
Is  it  burning?  How  does  it  make  light? 

What  happens  when  you  press  the  button  or  turn 
the  electric  switch?  Wliere  does  the  electricity  enter 
your  home?  How  many  wires  are  there?  To  what 
are  the  wires  connected  inside  the  building?  What  is 
the  use  of  the  meter? 

Study  the  street  lights  in  your  town.  Are  they  all 
of  the  same  kind?  Compare  with  one  another  and 


LIGHT  AND  LIGHTING  333 

tube,  a  rubber  stopper  with  a  hole  in  it,  and  a  piece  of 
glass  tubing  about  six  inches  long  that  fits  tight  in 
the  stopper.  Place  a  piece  of  soft  coal  about  the  size 
of  a  hickory  nut  in  the  test  tube.  Put  in  the  rubber 
stopper.  Hold  the  test  tube  almost  horizontally, 
tipped  slightly  downward  at  the  mouth.  With  an 
alcohol  lamp  heat  the  coal.  When  the  vapor  comes 
out  of  the  tube  light  it  and  you  have  a  small  gas  jet. 

Explanation.  Most  gas  lamps  have  a  mantle  which 
conceals  the  flame.  The  flame  is  what  is  known  as  a 
blue  flame.  It  is  veiy  hot  but  not  bright  so  it  gives 
a  very  poor  light.  But  the  mantle  becomes  so  hot 
that  it  glows  with  a  white  heat  and  produces  a  very 
good  light.  With  this  kind  of  a  light  the  air  enters 
at  the  air  openings  on  the  side  of  the  tube.  When 
you  turn  the  gas  on  it  mixes  with  the  air  before  it 
reaches  the  flame.  A  lamp  that  has  the  air  and  gas 
supply  mixed  in  proper  proportions  makes  a  hot 
blue  flame. 

In  the  open  jet  the  air  mixes  with  the  gas  as  it 
burns.  This  produces  a  flame  similar  to  that  of  the 
candle  or  kerosene  lamp.  It  does  not  produce  as  good 
a  light  as  the  lamp  with  the  mantle  and  it  burns  more 
gas. 

Different  kinds  of  gas  are  used  for  lighting  pur- 
poses. Some  people  have  their  own  gas  plants  and 
generate  a  gas  out  of  gasoline.  Others  have  acetylene 


334  STUDIES  IN  SCIENCE 

gas  machines.  In  some  places  natural  gas  that  is 
found  far  down  in  the  earth  is  used.  Wells  are  sunk 
and  the  gas  piped  from  them  to  buildings.  Many 
towns  and  cities  manufacture  gas  from  coal  or  other 
materials  and  pipe  this  to  homes  and  other  buildings. 
It  flows  through  a  meter  in  each  house  and  by  a 
device  the  amount  used  is  measured  in  cubic  feet. 
The  price  of  gas  varies  in  different  places  from  eighty 
cents  to  one  dollar  and  twenty-five  cents  per  1,000 
cubic  feet. 

Electric  lights.  Examine  an  electric  light  bulb. 
What  do  you  find?  Turn  on  the  electricity.  Is  there 
any  flame  in  the  bulb?  What  produces  the  light? 

Experiment.  A  light  without  a  flame.  Put  an  iron 
poker  in  the  stove  or  furnace  and  allow  it  to  remain 
until  it  is  very  hot,  then  take  it  out  and  hold  it, 
heated  end  up,  in  a  dark  room  noting  the  light  that 
it  gives  out.  If  there  were  some  way  that  you  could 
keep  it  white  hot  would  it  light  a  room  fairly  well? 
Is  it  burning?  How  does  it  make  light? 

What  happens  when  you  press  the  button  or  turn 
the  electric  switch?  Where  does  the  electricity  enter 
your  home?  How  many  wires  are  there?  To  what 
are  the  wires  connected  inside  the  building?  What  is 
the  use  of  the  meter? 

Study  the  street  lights  in  your  town.  Are  they  all 
of  the  same  kind?  Compare  with  one  another  and 


LIGHT  AND  LIGHTING  335 

with  those  used  in  your  home  or  other  buildings.  In 
each  case  determine  the  route  by  which  the  electri- 
city gets  from  the  power  house  to  the  lamp. 

Explanation.  In  cities,  and  even  in  some  rural 
districts,  electric  lights  are  fast  taking  the  place  of 
all  other  kinds  because*  they  are  most  convenient  and 
give  the  best  light  in  proportion  to  the  cost. 

You  observed  that  the  light  in  the  bulb  is  made  by 
a  fine  wire,  which  becomes  very  hot  and  glows  just  as 
the  end  of  the  poker  did  in  your  experiment.  When 
you  press  the  button  you  cause  a  current  of  electricity 
to  flow  through  the  wire  in  the  lamp,  and  this  causes 
the  wire  to  become  hot.  There  is  no  burning  con- 
nected with  it.  When  a  body  is  heated  to  a  white 
heat,  it  is  said  to  be  heated  to  incandescence;  so  this 
kind  of  electric  light  is  called  an  incandescent  light. 

The  electricity  is  generated  in  the  power  house 
and  flows  along  wires  in  the  street  or  ground  known 
as  line  wires.  Other  wires  extend  from  these  to  the 
buildings.  When  you  press  the  button  you  simply 
connect  the  line  wire  with  the  lamps  so  that  the 
current  may  flow  through  it.  Electricity  flows  more 
readily  through  copper  than  through  other  metals. 
The  finer  the  wire  the  more  resistance  is  offered  to 
the  current.  Line  wires  are  made  of  rather  large 
copper  wire.  The  incandescent  lamp  has  either  a  very 
fine  carbon  or  tungsten  filament  which  offers  such  a 


336 


STUDIES  IN  SCIENCE 


great  resistance  to  the  current  that  it  becomes  very 
hot  and  thus  gives  light.  Tungsten  is  coming  into 
use  more  and  more  since,  with  the  same  strength  of 
electricity,  it  gives  almost  three  times  as  intense  a 
light  as  the  carbon.  It  is  more  expensive,  but  because 
of  its  greater  efficiency  it  is  more  economical  in  the 
long  run. 

EYES 

Look  into  a  mirror  and  note  all  the  different  parts 
of  your  eye.  Look  at  an  eye  of  one  of  your  class- 
mates. 

.  Sclerotic 

Choroid 


Aqueous 
humor 


Fig.  65.     Section  of  the  eye. 

The  parts  that  you  can  see  are:  (1)  The  eyelids 
with  their  lashes.  These  ate  to  protect  the  eye  from 
dust  and  other  foreign  objects.  (2)  A  small  part  of 


LIGHT  AND  LIGHTING  335 

with  those  used  in  your  home  or  other  buildings.  In 
each  case  determine  the  route  by  which  the  electri- 
city gets  from  the  power  house  to  the  lamp. 

Explanation.  In  cities,  and  even  in  some  rural 
districts,  electric  lights  are  fast  taking  the  place  of 
all  other  kinds  because  they  are  most  convenient  and 
give  the  best  light  in  proportion  to  the  cost. 

You  observed  that  the  light  in  the  bulb  is  made  by 
a  fine  wire,  which  becomes  very  hot  and  glows  just  as 
the  end  of  the  poker  did  in  your  experiment.  When 
you  press  the  button  you  cause  a  current  of  electricity 
to  flow  through  the  wire  in  the  lamp,  and  this  causes 
the  wire  to  become  hot.  There  is  no  burning  con- 
nected with  it.  When  a  body  is  heated  to  a  white 
heat,  it  is  said  to  be  heated  to  incandescence;  so  this 
kind  of  electric  light  is  called  an  incandescent  light. 

The  electricity  is  generated  in  the  power  house 
and  flows  along  wires  in  the  street  or  ground  known 
as  line  wires.  Other  wires  extend  from  these  to  the 
buildings.  When  you  press  the  button  you  simply 
connect  the  line  wire  with  the  lamps  so  that  the 
current  may  flow  through  it.  Electricity  flows  more 
readily  through  copper  than  through  other  metals. 
The  finer  the  wire  the  more  resistance  is  offered  to 
the  current.  Line  wires  are  made  of  rather  large 
copper  wire.  The  incandescent  lamp  has  either  a  very 
fine  carbon  or  tungsten  filament  which  offers  such  a 


336 


STUDIES  IN  SCIENCE 


great  resistance  to  the  current  that  it  becomes  very 
hot  and  thus  gives  light.  Tungsten  is  coming  into 
use  more  and  more  since,  with  the  same  strength  of 
electricity,  it  gives  almost  three  times  as  intense  a 
light  as  the  carbon.  It  is  more  expensive,  but  because 
of  its  greater  efficiency  it  is  more  economical  in  the 
long  run. 

EYES 

Look  into  a  mirror  and  note  all  the  different  parts 
of  your  eye.  Look  at  an  eye  of  one  of  your  class- 
mates. 

•  Sclerotic 

Choroid 


Optic  Nerve 


Aqueous 
humor 


Fig.  65.     Section  of  the  eye. 

The  parts  that  you  can  see  are:  (1)  The  eyelids 
with  their  lashes.  These  aie  to  protect  the  eye  from 
dust  and  other  foreign  objects.  (2)  A  small  part  of 


LIGHT  AND  LIGHTING  337 

the  eyeball  with  the  white  covering.  (3)  In  front  you 
see  the  colored  part  of  the  eye  known  as  the  iris. 
In  the  center  of  this  is  the  dark  round  spot  called  the 
pupil.  The  iris  and  pupil  are  covered  with  a  trans- 
parent covering  called  the  cornea.  If  you  could  see 
your  entire  eye  you  would  find  that  the  ball  fills  a 
bony  socket  which  you  can  feel  surrounding  the  eye. 
On  the  inside  of  the  ball  back  of  the  iris  is  a  little 
watery  fluid  and  back  of  this  is  a  lens  known  as  the 
crystalline  lens.  The  rest  of  the  ball  is  filled  with  a 
semi-liquid  substance  somewhat  clearer  than  the  white 
of  an  egg  called  vitreous  humor.  On  the  inside  of 
the  wall  next  to  the  white  coat  is  a  dark  coat  and 
inside  of  this  is  the  retina,  which  is  really  the  spread 
out  optic  nerve. 

Bays  of  light  pass  from  any  object  you  are  looking' 
at  through  the  pupil,  then  through  the  lens  and  an 
image  of  the  object  is  thrown  upon  the  retina.  This 
in  some  way  stimulates  the  optic  nerve  which  carries 
the  sensation  to  the  brain  and  thus  you  see  the  object. 
The  plates  or  film  of  a  camera  receive  picture  impres- 
sions in  much  the  same  way  that  the  retina  does. 

Care  of  the  eyes.  Eyes  are  such  delicate  yet  won- 
derful devices  for  seeing  that  they  should  receive  the 
greatest  care.  They  may  be  permanently  injured  by 
using  them  in  a  bad  light.  People  everywhere  are 
giving  more  attention  to  the  proper  lighting  of  homes, 


338  STUDIES  IN  SCIENCE 

schools,  libraries  and  other  buildings.  Light  that 
comes  from  above  is  better  than  light  that  is  on  a 
level  with  the  eyes.  Window  shades  in  many  schools 
are  adjusted  so  that  the  lower  part  of  the  window 
may  be  covered  with  the  shade  while  the  upper  por- 
tion admits  the  light. 

The  light  from  an  ordinary  kerosene  lamp,  gas  jet, 
or  clear  glass  electric  bulb  is  called  direct  light.  If 
the  direct  rays  are  broken  up  by  reflection  from  an 
uneven  surface,  as  a  papered  wall  or  ceiling,  or  by 
passing  through  white  or  frosted  globes  or  window 
cu^ains,  the  light  is  diffused.  Diffused  light  is  much 

for  the  eyes  than  direct  light. 
>tudy  the  lighting  arrangements  in  your  home  and 
school.    Decide  which  kind  of  light  you  are  using. 

Placing  a  shade  over  an  ordinary  lamp  will  aid 
greatly  in  softening  and  diffusing  the  rays.  In  using 
any  artificial  or  natural  light  sit  so  that  the  light 
will  strike  your  work  over  the  left  shoulder.  Beading 
while  lying  down  causes  a  great  strain  upon  the  eyes. 

Whenever  there  are  any  indications  that  something 
is  wrong  with  the  eyes,  an  oculist  should  be  consulted 
at  once.  In  many  schools  children's  eyes  are  tested 
once  each  year.  Many  really  bright  pupils  are  con- 
sidered dull  simply  because  their  eyesight  is  defec- 
tive and  they  cannot  see  well  enough  to  do  their 
work  properly. 


LIGHT  AND  LIGHTING  337 

the  eyeball  with  the  white  covering.  (3)  In  front  you 
see  the  colored  part  of  the  eye  known  as  the  iris. 
In  the  center  of  this  is  the  dark  round  spot  called  the 
pupil.  The  iris  and  pupil  are  covered  with  a  trans- 
parent covering  called  the  cornea.  If  you  could  see 
your  entire  eye  you  would  find  that  the  ball  fills  a 
bony  socket  which  you  can  feel  surrounding  the  eye. 
On  the  inside  of  the  ball  back  of  the  iris  is  a  little 
watery  fluid  and  back  of  this  is  a  lens  known  as  the 
crystalline  lens.  The  rest  of  the  ball  is  filled  with  a 
semi-liquid  substance  somewhat  clearer  than  the  white 
of  an  egg  called  vitreous  humor.  On  the  inside  of 
the  wall  next  to  the  white  coat  is  a  dark  coat  and 
inside  of  this  is  the  retina,  which  is  really  the  spread 
out  optic  nerve. 

Eays  of  light  pass  from  any  object  you  are  looking' 
at  through  the  pupil,  then  through  the  lens  and  an 
image  of  the  object  is  thrown  upon  the  retina.  This 
in  some  way  stimulates  the  optic  nerve  which  carries 
the  sensation  to  the  brain  and  thus  you  see  the  object. 
The  plates  or  film  of  a  camera  receive  picture  impres- 
sions in  much  the  same  way  that  the  retina  does. 

Care  of  the  eyes.  Eyes  are  such  delicate  yet  won- 
derful devices  for  seeing  that  they  should  receive  the 
greatest  care.  They  may  be  permanently  injured  by 
using  them  in  a  bad  light.  People  everywhere  are 
giving  more  attention  to  the  proper  lighting  of  homes, 


338  STUDIES  IN  SCIENCE 

schools,  libraries  and  other  buildings.  Light  that 
comes  from  above  is  better  than  light  that  is  on  a 
level  with  the  eyes.  Window  shades  in  many  schools 
are  adjusted  so  that  the  lower  part  of  the  window 
may  be  covered  with  the  shade  while  the  upper  por- 
tion admits  the  light. 

The  light  from  an  ordinary  kerosene  lamp,  gas  jet, 
or  clear  glass  electric  bulb  is  called  direct  light.  If 
the  direct  rays  are  broken  up  by  reflection  from  an 
uneven  surface,  as  a  papered  wall  or  ceiling,  or  by 
passing  through  white  or  frosted  globes  or  window 
curtains,  the  light  is  diffused.  Diffused  light  is  much 
better  for  the  eyes  than  direct  light. 

Study  the  lighting  arrangements  in  your  home  and 
school.  Decide  which  kind  of  light  you  are  using. 

Placing  a  shade  over  an  ordinary  lamp  will  aid 
greatly  in  softening  and  diffusing  the  rays.  In  using 
any  artificial  or  natural  light  sit  so  that  the  light 
will  strike  your  work  over  the  left  shoulder.  Reading 
while  lying  down  causes  a  great  strain  upon  the  eyes. 

Whenever  there  are  any  indications  that  something 
is  wrong  with  the  eyes,  an  oculist  should  be  consulted 
at  once.  In  many  schools  children's  eyes  are  tested 
once  each  year.  Many  really  bright  pupils  are  con- 
sidered dull  simply  because  their  eyesight  is  defec- 
tive and  they  cannot  see  well  enough  to  do  their 
work  properly. 


CHAPTER  XX 

WATER  SUPPLY 

Materials.  The  water  supply  of  the  school  and 
home;  a  faucet,  drinking  fountain;  water  pipes,  reser- 
voir, standpipe;  wells,  pumps. 

Water  supply  of  the  school.  How  are  you  sup- 
plied with  drinking  water  in  your  school  building? 
If  from  a  pail  or  jar,  what  precaution  is  taken  to 
keep  it  free  from  dust?  Are  individual  drinking 
cups  used?  How  do  you  get  the  water  from  the  pail 
into  your  cup? 

If  you  have  a  drinking  fountain,  study  it.  How 
many  distinct  parts  do  you  find?  How  many  pipes 
are  connected  with  it?  What  is  the  use  of  each?  Of 
the  basin?  When  you  turn  the  faucet  what  happens? 
Why  does  the  water  flow  out?  Where  does  it  come 
from?  How  do  you  stop  the  flow?  To  answer  this, 
examine  an  unattached  faucet.  Look  through  it 
while  you  turn  the  handle  back  and  forth. 

Study  faucets  at  home.  Can  you  turn  the  faucet 
and  leave  it  so  the  water  will  continue  to  run  until 
you  turn  it  back,  or  does  the  water  stop  running 
the  moment  you  stop  pressing  on  the  handle  or 

339 


340  STUDIES  IN  SCIENCE 

spigot?  Where  does  the  water  come  from  that  stands 
in  the  pipe  ready  to  flow  the  moment  you  turn  the 
faucet?  Does  the  water  flow  slowly  or  rapidly?  If 
there  are  fountains  or  lavatories  on  different  floors 
of  the  building,  test  them  to.  determine  whether  there 
is  any  difference  in  the  force  with  which  the  water 
flows. 

Trace  the  water-pipe  to  the  basement  of  the  build- 
ing. Find  where  it  enters.  How  deep  in  the  ground 
is  it?  What  is  the  size  of  the  pipe?  When  a  plumber 
speaks  of  an  inch  and  a  quarter  pipe,  does  he  mean 
the  diameter  or  the  circumference? 

Where  does  the  pipe  come  from  into  the  basement? 
If  you  could  trace  it  underground,  with  what  would 
you  find  it  connected? 

Explanation.  No  matter  what  kind  of  drinking 
fountain  you  examine,  you  will  find  it  has  an  opening 
for  the  water,  a  water-pipe,  a  basin  to  catch  the 
water,  and  a  drain  pipe  from  this.  Some  fountains 
are  so  enclosed  that  you  cannot  see  the  pipes. 

The  faucet  has  a  valve  in  it  which  closes  the  open- 
ing completely  when  you  turn  it  in  one  direction  and 
opens  it  when  you  turn  it  in  the  opposite  direction. 
Some  faucets  have  a  spring  arranged  so  that  when 
you  cease  to  press,  the  valve  closes  and  stops  the 
flow  of  water.  This  is  called  a  spring  faucet. 

You  know  from  the  way  the  water  pours  out  when 


CHAPTER  XX 

WATEK  SUPPLY 

Materials.  The  water  supply  of  the  school  and 
home;  a  faucet,  drinking  fountain;  water  pipes,  reser- 
voir, standpipe;  wells,  pumps. 

Water  supply  of  the  school.  How  are  you  sup- 
plied with  drinking  water  in  your  school  building? 
If  from  a  pail  or  jar,  what  precaution  is  taken  to 
keep  it  free  from  dust?  Are  individual  drinking 
cups  used!  How  do  you  get  the  water  from  the  pail 
into  your  cup? 

If  you  have  a  drinking  fountain,  study  it.  How 
many  distinct  parts  do  you  find?  How  many  pipes 
are  connected  with  it?  What  is  the  use  of  each?  Of 
the  basin?  When  you  turn  the  faucet  what  happens? 
Why  does  the  water  flow  out?  Where  does  it  come 
from?  How  do  you  stop  the  flow?  To  answer  this, 
examine  an  unattached  faucet.  Look  through  it 
while  you  turn  the  handle  back  and  forth. 

Study  faucets  at  home.  Can  you  turn  the  faucet 
and  leave  it  so  the  water  will  continue  to  run  until 
you  turn  it  back,  or  does  the  water  stop  running 
the  moment  you  stop  pressing  on  the  handle  or 

339 


340  STUDIES  IN  SCIENCE 

spigot?  Where  does  the  water  come  from  that  stands 
in  the  pipe  ready  to  flow  the  moment  you  turn  the 
faucet?  Does  the  water  flow  slowly  or  rapidly!  If 
there  are  fountains  or  lavatories  on  different  floors 
of  the  building,  test  them  to  determine  whether  there 
is  any  difference  in  the  force  with  which  the  water 
flows. 

Trace  the  water-pipe  to  the  basement  of  the  build- 
ing. Find  where  it  enters.  How  deep  in  the  ground 
is  it?  What  is  the  size  of  the  pipe?  When  a  plumber 
speaks  of  an  inch  and  a  quarter  pipe,  does  he  mean 
the  diameter  or  the  circumference? 

Where  does  the  pipe  come  from  into  the  basement? 
If  you  could  trace  it  underground,  with  what  would 
you  find  it  connected? 

Explanation.  No  matter  what  kind  of  drinking 
fountain  you  examine,  you  will  find  it  has  an  opening 
for  the  water,  a  water-pipe,  a  basin  to  catch  the 
water,  and  a  drain  pipe  from  this.  Some  fountains 
are  so  enclosed  that  you  cannot  see  the  pipes. 

The  faucet  has  a  valve  in  it  which  closes  the  open- 
ing completely  when  you  turn  it  in  one  direction  and 
opens  it  when  you  turn  it  in  the  opposite  direction. 
Some  faucets  have  a  spring  arranged  so  that  when 
you  cease  to  press,  the  valve  closes  and  stops  the 
flow  of  water.  This  is  called  a  spring  faucet. 

You  know  from  the  way  the  water  pours  out  when 


WATER  SUPPLY  341 

you  turn  the  faucet  that  it  must  be  standing  in  the 
pipe  ready  to  flow  the  moment  it  has  a  chance.  In 
the  basement  you  found  the  water-pipe  coming  in 
from  the  ground.  If  you  could  trace  this  outward, 
you  would  find  it  extending  to  the  street  where  it 
is  connected  with  a,  large  pipe.  The  large  pipes 
are  called  water  mains.  The  size  depends  upon  the 
amount  of  water  needed  by  the  people  living  along 
the  street.  In  large  cities  they  are  much  larger  than 
in  small  towns.  They  vary  from  eight  inches  to  two 
or  three  feet  in  diameter. 

If  you  follow  the  main  you  finally  come  to  a  stand- 
pipe  or  a  reservoir  and  a  pumping  station,  usually 
near  the  source  of  the  water  supply. 

Visit  the  pumping  station  and  have  the  man  in 
charge  show  you  the  pumps  and  explain  their  use. 
You  may  find  one  pumping  water  into  the  reservoir, 
another  pumping  it  into  mains  or  a  stand-pipe. 
Visit  the  reservoir  if  possible.  Get  its  dimension 
and  determine  how  much  water  it  will  hold.  Study 
also  the  stand-pipe.  How  high  is  it?  What  is  its 
function?  Can  you  make  a  piece  of  apparatus  that 
will  show  the  principle  of  the  stand-pipe? 

The  force  with  which  the  water  pours  out  of  a 
faucet  may  be  due  to  the  pump  at  the  pumping 
station  or  to  the  stand-pipe.  Often  the  water  is 
pumped  directly  into  the  mains.  The  pressure  of  the 


342  STUDIES  IN  SCIENCE 

persistent  flow  coming  from  the  pump  forces  the 
water  along  through  the  mains  and  up  into  the  pipes. 
The  force  from  the  stand-pipe  is  due  to  the  pressure 
of  the  water  itself.  The  stand-pipe  is  connected  with 
the  mains,  and  when  it  is  full  the  pressure  is  suffi- 
cient to  force  the  water  into  the  pipes.  Some  force 
is  lost  by  friction  as  the  water  flows  along,  so  the 
highest  faucet  in  the  water  system  can  not  be  quite 
as  high  as  the  water  in  the  stand-pipe. 

Where  does  the  water  come  from  that  is  pumped 
into  the  reservoir  or  stand-pipe!  If  the  water  is 
obtained  from  a  river,  find  out  how  far  away  the 
river  is  and  how  the  water  gets  from  the  river  into 
the  reservoir.  If  the  source  is  a  lake  make  the  same 
investigation.  How  far  out  from  the  shore  is  the 
water  procured? 

Wells.  If  you  live  where  wells  supply  the  water, 
find  out  how  many  kinds  of  wells  there  are  in  your 
district.  Study  the  well  on  the  school  grounds.  Is  it 
a  drilled  or  dug  well?  How  many  people  in  the  com- 
munity use  water  from  dug  wells?  What  is  the 
average  depth  of  these  wells?  The  diameter?  With 
what  are  they  walled  up?  Does  the  water  level  in 
them  vary  from  time  to  time?  Locate  wells  that  go 
dry  in  the  summer?  Explain  why. 

How  many  drilled  wells  are  there  in  the  com- 
munity? Find  out  how  deep  some  of  these  are. 


WATER  SUPPLY  341 

you  turn  the  faucet  that  it  must  be  standing  in  the 
pipe  ready  to  flow  the  moment  it  has  a  chance.  In 
the  basement  you  found  the  water-pipe  coming  in 
from  the  ground.  If  you  could  trace  this  outward, 
you  would  find  it  extending  to  the  street  where  it 
is  connected  with  a  large  pipe.  The  large  pipes 
are  called  water  mains.  The  size  depends  upon  the 
amount  of  water  needed  by  the  people  living  along 
the  street.  In  large  cities  they  are  much  larger  than 
in  small  towns.  They  vary  from  eight  inches  to  two 
or  three  feet  in  diameter. 

If  you  follow  the  main  you  finally  come  to  a  stand- 
pipe  or  a  reservoir  and  a  pumping  station,  usually 
near  the  source  of  the  water  supply. 

Visit  the  pumping  station  and  have  the  man  in 
charge  show  you  the  pumps  and  explain  their  use. 
You  may  find  one  pumping  water  into  the  reservoir, 
another  pumping  it  into  mains  or  a  stand-pipe. 
Visit  the  reservoir  if  possible.  Get  its  dimension 
and  determine  how  much  water  it  will  hold.  Study 
also  the  stand-pipe.  How  high  is  it?  What  is  its 
function!  Can  you  make  a  piece  of  apparatus  that 
will  show  the  principle  of  the  stand-pipe? 

The  force  with  which  the  water  pours  out  of  a 
faucet  may  be  due  to  the  pump  at  the  pumping 
station  or  to  the  stand-pipe.  Often  the  water  is 
pumped  directly  into  the  mains.  The  pressure  of  the 


342  STUDIES  IN  SCIENCE 

persistent  flow  coming  from  the  pump  forces  the 
water  along  through  the  mains. and  up  into  the  pipes. 
The  force  from  the  stand-pipe  is  due  to  the  pressure 
of  the  water  itself.  The  stand-pipe  is  connected  with 
the  mains,  and  when  it  is  full  the  pressure  is  suffi- 
cient to  force  the  water  into  the  pipes.  Some  force 
is  lost  by  friction  as  the  water  flows  along,  so  the 
highest  faucet  in  the  water  system  can  not  be  quite 
as  high  as  the  water  in  the  stand-pipe. 

Where  does  the  water  come  from  that  is  pumped 
into  the  reservoir  or  stand-pipe!  If  the  water  is 
obtained  from  a  river,  find  out  how  far  away  the 
river  is  and  how  the  water  gets  from  the  river  into 
the  reservoir.  If  the  source  is  a  lake  make  the  same 
investigation.  How  far  out  from  the  shore  is  the 
water  procured! 

Wells.  If  you  live  where  wells  supply  the  water, 
find  out  how  many  kinds  of  wells  there  are  in  your 
district.  Study  the  well  on  the  school  grounds.  Is  it 
a  drilled  or  dug  well!  How  many  people  in  the  com- 
munity use  water  from  dug  wells!  What  is  the 
average  depth  of  these  wells!  The  diameter!  With 
what  are  they  walled  up!  Does  the  water  level  in 
them  vary  from  time  to  time!  Locate  wells  that  go 
dry  in  the  summer!  Explain  why, 

How  many  drilled  wells  are  there  in  the  com- 
munity! Find  out  how  deep  some  of  these  are. 


WATER  SUPPLY  343 

What  is  their  diameter?  Are  there  any  artesian  or 
flowing  wells? 

Experiment.  What  is  the  source  of  water  in  shal- 
low or  dug  wells! 

Into  a  shallow  pan  put  a  layer  of  soil  or  sand. 
About  half  way  from  the  center  make  a  hole  similar 
to  a  dug  well  and  wall  it  up  with  pebbles  or  bits  of 
rock.  Continue  filling  in  soil  and  walling  up  the  well 
till  the  pan  is  well  filled.  The  soil  should  slope 
toward  the  part  of  the  pan  in  which  the  well  is 
located.  Now  pour  water  over  the  surface.  When 
the  water  disappears  put  on  some  more.  Continue 
till  the  soil  seems  well  saturated.  Watch  the  well 
and  describe  what  takes  place.  Determine  whether 
or  not  water  comes  into  the  well  from  all  sides.  To 
what  extent  does  the  slope  affect  the  amount  of 
water  that  flows  into  the  well? 

If  this  were  a  real  well  and  the  soil  in  the  pan 
were  a  plot  of  ground  where  you  were  to  build  a 
home  with  a  barn  and  all  other  buildings,  where 
would  you  place  the  house?  The  other  buildings? 
Where  the  well?  Why? 

Explanation.  Your  experiment  shows  the  simple 
principle  by  which  shallow,  dug  wells  are  supplied 
with  water.  The  rain  that  falls  upon  the  ground 
percolates  or  moves  slowly  downward.  If  there  is 
a  slope  the  water  accumulates  in  the  lowest  places. 


344  STUDIES  IN  SCIENCE 

"When  a  well  is  dug  the  water  in  the  ground  flows 
into  the  hole  from  all  sides  just  as  it  did  in  the 
experiment.  The  higher  the  water  stands  in  the  sur- 
rounding soil  the  higher  it  stands  in  the  well.  The 
line  which  marks  the  upper  surface  of  the  water  is 
called  the  ground  water  level.  During  dry  weather 
this  level  may  sink  below  the  bottom  of  the  well 
and  then  the  well  becomes  dry. 

Wells  should  be  placed  in  relation  to  barns  and 
other  buildings  so  that  water  from  around  these  will 
not  flow  into  the  wells.  It  is  often  safer  to  dig  wells 
in  the  higher  ground  where  they  must  necessarily 
be  made  deeper. 

Experiment.  What  is  the  source  of  the  water  in 
deep,  drilled  wells! 

Procure  a  large  pan;  a  wide  granite  dish  pan  will 
serve.  Put  a  sloping  layer  of  cement  in  the  bottom. 
To  make  the  cement,  mix  together  Portland  cement, 
sand  and  water  in  the  proportion  1/3  cement,  2/3 
sand.  On  this  place  a  sloping  layer  of  sand,  then 
mother  layer  of  cement.  This  should  not  cover  the 
last  three  or  four  inches  of  sand  in  the  highest  part. 
Place  a  layer  of  soil  over  this.  Insert  a  glass  tube 
into  the  lowest  part  of  the  sand  layer.  Do  this  before 
you  put  on  the  top  layer  of  cement.  This  represents 
a  drilled  well.  Firm  the  cement  closely  around  the 
tube  and  also  around  the  sides  of  the  pan.  Pour 


WATER  SUPPLY  343 

What  is  their  diameter?  Are  there  any  artesian  or 
flowing  wells? 

Experiment.  What  is  the  source  of  water  in  shal- 
low or  dug  wells! 

Into  a  shallow  pan  put  a  layer  of  soil  or  sand. 
About  half  way  from  the  center  make  a  hole  similar 
to  a  dug  well  and  wall  it  up  with  pebbles  or  bits  of 
rock.  Continue  filling  in  soil  and  walling  up  the  well 
till  the  pan  is  well  filled.  The  soil  should  slope 
toward  the  part  of  the  pan  in  which  the  well  is 
located.  Now  pour  water  over  the  surface.  When 
the  water  disappears  put  on  some  more.  Continue 
till  the  soil  seems  well  saturated.  Watch  the  well 
and  describe  what  takes  place.  Determine  whether 
or  not  water  comes  into  the  well  from  all  sides.  To 
what  extent  does  the  slope  affect  the  amount  of 
water  that  flows  into  the  well? 

If  this  were  a  real  well  and  the  soil  in  the  pan 
were  a  plot  of  ground  where  you  were  to  build  a 
home  with  a  barn  and  all  other  buildings,  where 
would  you  place  the  house?  The  other  buildings? 
Where  the  well?  Why? 

Explanation.  Your  experiment  shows  the  simple 
principle  by  which  shallow,  dug  wells  are  supplied 
with  water.  The  rain  that  falls  upon  the  ground 
percolates  or  moves  slowly  downward.  If  there  is 
a  slope  the  water  accumulates  in  the  lowest  places. 


344  STUDIES  IN  SCIENCE 

When  a  well  is  dug  the  water  in  the  ground  flows 
into  the  hole  from  all  sides  just  as  it  did  in  the 
experiment.  The  higher  the  water  stands  in  the  sur- 
rounding soil  the  higher  it  stands  in  the  well.  The 
line  which  marks  the  upper  surface  of  the  water  is 
called  the  ground  water  level.  During  dry  weather 
this  level  may  sink  below  the  bottom  of  the  well 
and  then  the  well  becomes  dry. 

Wells  should  be  placed  in  relation  to  barns  and 
other  buildings  so  that  water  from  around  these  will 
not  flow  into  the  wells.  It  is  often  safer  to  dig  wells 
in  the  higher  ground  where  they  must  necessarily 
be  made  deeper. 

Experiment.  What  is  the  source  of  the  water  in 
deep,  drilled  wells? 

Procure  a  large  pan;  a  wide  granite  dish  pan  will 
serve.  Put  a  sloping  layer  of  cement  in  the  bottom. 
To  make  the  cement,  mix  together  Portland  cement, 
sand  and  water  in  the  proportion  1/3  cement,  2/3 
sand.  On  this  place  a  sloping  layer  of  sand,  then 
another  layer  of  cement.  This  should  not  cover  the 
last  three  or  four  inches  of  sand  in  the  highest  part. 
Place  a  layer  of  soil  over  this.  Insert  a  glass  tube 
into  the  lowest  part  of  the  sand  layer.  Do  this  before 
you  put  on  the  top  layer  of  cement.  This  represents 
a  drilled  well.  Firm  the  cement  closely  around  the 
tube  and  also  around  the  sides  of  the  pan.  Pour 


WATER  SUPPLY  345 

water  on  the  sand.  Watch  the  well.  How  high  does 
the  water  stand  in  it?  Can  any  water  from  the  layer 
of  top  soil  get  into  it?  Why! 

Springs.  To  what  extent  do  springs  furnish  water 
in  the  region  where  you  live?  Describe  a  spring  if 
there  is  one  near  by.  Is  the  water  cool  or  warm? 
Does  it  flow  constantly?  Is  the  region  level  or  hilly? 
Are  there  any  rivers  or  creeks  near  by?  How  do 
you  account  for  springs? 

Explanation.  If  your  experiment  worked  prop- 
erly, you  have  a  clear  illustration  of  how  water  is 
supplied  in  drilled  wells.  The  different  layers  of 
soil  in  the  pan  represent  an  area  on  the  earth's  sur- 
face where  there  is  a  layer  of  sand  between  two 
impervious  layers  of  material  such  as  solid  rock  or 
fine  clay.  The  sand  layer  comes  to  the  surface  many 
miles  away  from  the  spot  where  the  well  is  drilled. 
Rain  falling  upon  this  sinks  down  into  the  sand  and 
moves  slowly  down  the  slope.  Since  there  is  an 
impervious  layer  under  the  sand  the  water  cannot 
move  farther  down,  so  the  sand  becomes  saturated 
with  water  and  forms  a  vein.  When  the  well  is 
drilled  through  the  upper  layer  into  this  the  water  in 
the  vein  rises  through  the  open  bottom  of  the  pipe 
and  stands  as  high  as  the  water  extends  into  the  sand 
layer.  No  water  from  the  soil  near  the  well  can  enter 
through  the  iron  pipe.  It  cannot  reach  the  sand 


346  STUDIES  IN  SCIENCE 

layer  which  supplies  the  water  because  of  the  imper- 
vious layer  on  top  of  the  sand. 

Springs  are  due  to  precisely  the  same  conditions 
as  those  described  above  except  that  the  water  makes 
its  way  to  the  surface  and  flows  out. 

Water  and  health.  Which  of  the  systems  that  you 
have  studied  is  likely  to  supply  the  purest  water? 
Why! 

Water  may  have  several  different  kinds  of  impuri- 
ties in  it:  1.  It  may  have  sediment  which  consists 
of  small  particles  of  sand,  clay  or  bits  of  decaying 
matter.  Most  of  this  will  settle  to  the  bottom  of  a 
vessel  in  which  the  water  stands  quiet  for  some 
time.  Biver  water  is  likely  to  contain  more  sediment 
than  lake  or  well  water. 

2.  The    second    kind    of    impurity    is    dissolved 
mineral  compounds  of  various  kinds.     Perhaps  you 
have  drunk  water  from  springs  that  contained  a  vast 
amount  of  sulphur  or  other   substance.     This  kind 
of  impurity  does  not  as  a  rule  make  water  unhealth- 
ful.     In  fact,  some  waters  are  regarded  very  healthful 
because   of   the   minerals   dissolved   in   them.     Most 
well  water  has  considerable  lime  dissolved  in  it. 

3.  The  third  kind  of  impurity  consists  of  living 
organisms  in  the  water.    Certain  kinds  of  green  plants 
called  algae  sometimes  grow  on  the  walls  of  reser- 
voirs or  even  in  the  water.     They  are  not  in  them- 


WATER  SUPPLY  345 

water  on  the  sand.  Watch  the  well.  How  high  does 
the  water  stand  in  it?  Can  any  water  from  the  layer 
of  top  soil  get  into  it?  Why! 

Springs.  To  what  extent  do  springs  furnish  water 
in  the  region  where  you  live?  Describe  a  spring  if 
there  is  one  near  by.  Is  the  water  cool  or  warm? 
Does  it  flow  constantly?  Is  the  region  level  or  hilly? 
Are  there  any  rivers  or  creeks  near  by?  How  do 
you  account  for  springs? 

Explanation.  If  your  experiment  worked  prop- 
erly, you  have  a  clear  illustration  of  how  water  is 
supplied  in  drilled  wells.  The  different  layers  of 
soil  in  the  pan  represent  an  area  on  the  earth's  sur- 
face where  there  is  a  layer  of  sand  between  two 
impervious  layers  of  material  such  as  solid  rock  or 
fine  clay.  The  sand  layer  comes  to  the  surface  many 
miles  away  from  the  spot  where  the  well  is  drilled. 
Rain  falling  upon  this  sinks  down  into  the  sand  and 
moves  slowly  down  the  slope.  Since  there  is  an 
impervious  layer  under  the  sand  the  water  cannot 
move  farther  down,  so  the  sand  becomes  saturated 
with  water  and  forms  a  vein.  When  the  well  is 
drilled  through  the  upper  layer  into  this  the  water  in 
the  vein  rises  through  the  open  bottom  of  the  pipe 
and  stands  as  high  as  the  water  extends  into  the  sand 
layer.  No  water  from  the  soil  near  the  well  can  enter 
through  the  iron  pipe.  It  cannot  reach  the  sand 


346  STUDIES  IN  SCIENCE 

layer  which  supplies  the  water  because  of  the  imper- 
vious layer  on  top  of  the  sand. 

Springs  are  due  to  precisely  the  same  conditions 
as  those  described  above  except  that  the  water  makes 
its  way  to  the  surface  and  flows  out. 

Water  and  health.  Which  of  the  systems  that  you 
have  studied  is  likely  to  supply  the  purest  water? 
Why? 

Water  may  have  several  different  kinds  of  impuri- 
ties in  it:  1.  It  may  have  sediment  which  consists 
of  small  particles  of  sand,  clay  or  bits  of  decaying 
matter.  Most  of  this  will  settle  to  the  bottom  of  a 
vessel  in  which  the  water  stands  quiet  for  some 
time.  Eiver  water  is  likely  to  contain  more  sediment 
than  lake  or  well  water. 

2.  The    second    kind    of    impurity    is    dissolved 
mineral  compounds  of  various  kinds.     Perhaps  you 
have  drunk  water  from  springs  that  contained  a  vast 
amount  of  sulphur  or  other  substance.     This  kind 
of  impurity  does  not  as  a  rule  make  water  unhealth- 
ful.     In  fact,  some  waters  are  regarded  very  healthful 
because   of  the   minerals   dissolved   in   them.     Most 
well  water  has  considerable  lime  dissolved  in  it. 

3.  The  third  kind  of  impurity  consists  of  living 
organisms  in  the  water.    Certain  kinds  of  green  plants 
called  algae  sometimes  grow  on  the  walls  of  reser- 
voirs or  even  in  the  water.     They  are  not  in  them- 


WATER  SUPPLY  347 

selves  harmful.  The  living  organisms  that  are  to 
be  feared  are  bacteria,  since  they  may  produce  human 
diseases.  Chief  among  these  is  the  typhoid  fever 
germ.  Statistics  show  that  the  spread  of  typhoid 
fever  is  largely  through  drinking  water.  This  means 
that  the  germs  from  some  one  who  is  ill  with  typhoid 
get  into  the  water  supply.  If  the  supply  is  taken 
from  a  river,  it  sometimes  happens  that  the  water 
is  contaminated  several  miles  above  the  place  from 
which  water  is  taken.  You  can  see  how  easily  this 
might  happen  since  the  water  is  constantly  moving 
down-stream. 

The  same  thing  may  happen  when  the  supply  is 
from  a  lake.  The  bacteria  may  be  carried  into  the 
lake  by  drains  or  streams.  If  the  water  supply  is 
taken  from  too  near  the  shore,  some  of  the  bacteria 
may  be  distributed  over  the  city  in  the  water. 

Shallow  dug  wells  have  bacteria  carried  into  -them 
with  the  water  that  flows  near  barns,  outhouses  and 
other  places  where  there  is  waste  material  with  germs 
in  it.  Typhoid  fever  is  sometimes  called  a  country 
disease,  since  there  are  in  proportion  more  deaths  due 
to  this  dread  disease  in  the  country  and  small  towns 
than  in  cities.  The  reason,  of  course,  is  that  in  recent 
years  more  attention  has  been  given  in  cities  to  secur- 
ing pure  water. 

How  to  secure  pure  water.    The  drilled  well  sup- 


348  STUDIES  IN  SCIENCE 

plying  water  from  a  great  depth  is  usually  free  from 
all  disease  germs.  The  water  percolates  so  far 
through  the  beds  of  sand  or  gravel  that  any  bacteria 
which  may  have  been  in  it  are  killed.  The  deep 
well  then,  where  it  is  possible  to  secure  water  in  this 
way,  solves  the  problem  of  pure  water  in  the  country 
and  small  town.  Deep  wells  are  used  as  the  source 
of  city  water  supply  in  many  good-sized  towns  of 
the  Middle  West. 

Spring  water  is  usually  pure  for  the  same  reason 
that  deep  well  water  is.  Occasionally,  however, 
spring  water  is  contaminated  by  flowing  through 
bacteria  laden  soil  as  it  nears  the  surface  where  it 
flows  out. 

The  dug  well  and  pure  water.  The  dug  well  should 
be  placed  so  that  water  from  feed  lots,  barns  and 
outhouses  may  not  readily  drain  into  it.  The  last 
five  or  six  feet  of  a  deep  dug  well  may  be  finished 
with  a  layer  of  cement  over  the  brick  wall.  This 
prevents  the  ground  water  near  the  surface  from 
entering.  The  cement  wall  should  extend  five  or  six 
inches  above  the  surface  of  the  ground  and  should 
have  a  tight  cover  so  that  no  impurities  may  enter 
the  well  from  the  top.  A  deep  dug  well  often  reaches 
a  layer  of  saturated  sand,  a  vein,  which  supplies  pure 
water. 

Lakes    and    rivers.    Cities    that    use    lake    water 


WATER  SUPPLY  347 

selves  harmful.  The  living  organisms  that  are  to 
be  feared  are  bacteria,  since  they  may  produce  human 
diseases.  Chief  among  these  is  the  typhoid  fever 
germ.  Statistics  show  that  the  spread  of  typhoid 
fever  is  largely  through  drinking  water.  This  means 
that  the  germs  from  some  one  who  is  ill  with  typhoid 
get  into  the  water  supply.  If  the  supply  is  taken 
from  a  river,  it  sometimes  happens  that  the  water 
is  contaminated  several  miles  above  the  place  from 
which  water  is  taken.  You  can  see  how  easily  this 
might  happen  since  the  water  is  constantly  moving 
down-stream. 

The  same  thing  may  happen  when  the  supply  is 
from  a  lake.  The  bacteria  may  be  carried  into  the 
lake  by  drains  or  streams.  If  the  water  supply  is 
taken  from  too  near  the  shore,  some  of  the  bacteria 
may  be  distributed  over  the  city  in  the  water. 

Shallow  dug  wells  have  bacteria  carried  into  them 
with  the  water  that  flows  near  barns,  outhouses  and 
other  places  where  there  is.  waste  material  with  germs 
in  it.  Typhoid  fever  is  sometimes  called  a  country 
disease,  since  there  are  in  proportion  more  deaths  due 
to  this  dread  disease  in  the  country  and  small  towns 
than  in  cities.  The  reason,  of  course,  is  that  in  recent 
years  more  attention  has  been  given  in  cities  to  secur- 
ing pure  water. 

How  to  secure  pure  water.     The  drilled  well  sup- 


348  STUDIES  IN  SCIENCE 

plying  water  from  a  great  depth  is  usually  free  from 
all  disease  germs.  The  water  percolates  so  far 
through  the  beds  of  sand  or  gravel  that  any  bacteria 
which  may  have  been  in  it  are  killed.  The  deep 
well  then,  where  it  is  possible  to  secure  water  in  this 
way,  solves  the  problem  of  pure  water  in  the  country 
and  small  town.  Deep  wells  are  used  as  the  source 
of  city  water  supply  in  many  good-sized  towns  of 
the  Middle  West. 

Spring  water  is  usually  pure  for  the  same  reason 
that  deep  well  water  is.  Occasionally,  however, 
spring  water  is  contaminated  by  flowing  through 
bacteria  laden  soil  as  it  nears  the  surface  where  it 
flows  out. 

The  dug  well  and  pure  water.  The  dug  well  should 
be  placed  so  that  water  from  feed  lots,  barns  and 
outhouses  may  not  readily  drain  into  it.  The  last 
five  or  six  feet  of  a  deep  dug  well  may  be  finished 
with  a  layer  of  cement  over  the  brick  wall.  This 
prevents  the  ground  water  near  the  surface  from 
entering.  The  cement  wall  should  extend  five  or  six 
inches  above  the  surface  of  the  ground  and  should 
have  a  tight  cover  so  that  no  impurities  may  enter 
the  well  from  the  top.  A  deep  dug  well  often  reaches 
a  layer  of  saturated  sand,  a  vein,  which  supplies  pure 
water. 

Lakes    and    rivers.    Cities    that    use    lake    water 


WATER  SUPPLY  349 

usually  get  their  supply  from  deep  water  near  the 
center  of  the  lake.  This  is  accomplished  by  making 
tunnels  in  the  bottom  of  the  lake  extending  out  sev- 
eral miles.  In  some  cases  the  water  is  filtered  through 
beds  of  sand.  When  contamination  is  feared,  chem- 
icals are  used  in  the  water  to  kill  the  bacteria. 

Eiver  water  is  filtered  in  most  places.  The  bene- 
ficial results  that  come  from  attention  to  purifying 
the  water  supply  can  not  longer  be  questioned. 

Sewage,  How  to  dispose  of  sewage  is  a  problem 
that  always  goes  along  with  the  question  of  pure 
water.  If  you  studied  a  drinking  fountain  or  faucet, 
you  found  that  the  water  from  the  basin  or  sink 
disappeared  in  a  waste-pipe.  If  you  could  trace  this 
pipe,  you  would  find  it  connected  with  a  sewer  which 
opens  into  a  large  street  sewer.  Do  you  know  where 
the  sewers  of  your  town  discharge  their  contents? 
In  many  places  the  sewage  is  discharged  into  streams 
or  lakes.  From  what  we  have  already  said  you  can 
see  that  there  are  many  objections  to  this.  Probablj 
the  time  will  come  when  this  method,  except  perhaps 
in  the  largest  cities,  will  be  abandoned.  Many  small 
cities  are  installing  septic  tanks.  The  tank  is  a  large 
receptacle  of  two  or  three  compartments  which 
receives  the  sewage.  It  is  made  of  cement  so  it  is 
absolutely  water  tight.  Bacteria  act  upon  the.  mate- 
rial changing  it  to  gases  and  liquids  until  most  of  it 


350  STUDIES  IN  SCIENCE 

is  disposed  of.  The  small  amount  of  solid  matter 
known  as  sludge  is  occasionally  removed  from  the 
tanks  and  used  as  a  fertilizer. 

The  need  of  water.  The  human  body  is  composed 
of  different  organs  all  of  which  are  built  up  of  tis- 
sues. There  are  then  several  different  kinds  of  tissue 
in  the  body. 

Muscle  tissue  composes  the  flesh  and  makes  move- 
ments possible. 

Skin  tissue,  also  called  epithelium,  makes  the  out- 
side covering  of  the  body  as  well  as  the  lining  of  the 
mouth  and  other  inner  parts. 

Connective  tissue  is  a  membrane  that  helps  to  hold 
together  the  different  parts  of  the  body,  as  the  bun- 
dles of  muscle  fibers. 

Nerve  tissue  makes  up  the  brain  and  nerves. 
Fat  is  a  tissue  found  in  various  organs.    It  usually 
stores  up  material  for  future  use. 

Gland  tissue  composes  certain  organs  which  make 
secretions  for  use  in  the  body  as  the  saliva  in  the 
mouth  and  the  digestive  fluids  in  the  stomach. 

Bone  and  cartilage  tissue  are  the  solid,  supporting 
parts  of  the  body. 

Now  all  of  these  tissues  are  made  up  of  cells  so 
small  that  you  would  need  a  microscope  to  see  them. 
Each  cell  is  made  of  a  substance  called  protoplasm, 
and  this  is  composed  in  large  part  of  water,  so  that 


WATE&  SUPPLY 

usually  get  their  supply  from  deep  water  near  the 
center  of  the  lake.  This  is  accomplished  by  making 
tunnels  in  the  bottom  of  the  lake  extending  out  sev- 
eral miles.  In  some  cases  the  water  is  filtered  through 
beds  of  sand.  When  contamination  is  feared,  chem- 
icals are  used  in  the  water  to  kill  the  bacteria. 

River  water  is  filtered  in  most  places.  The  bene- 
ficial results  that  come  from  attention  to  purifying 
the  water  supply  can  not  longer  be  questioned. 

Sewage.  How  to  dispose  of  sewage  is  a  problem 
that  always  goes  along  with  the  question  of  pure 
water.  If  you  studied  a  drinking  fountain  or  faucet, 
you  found  that  the  water  from  the  basin  or  sink 
disappeared  in  a  waste-pipe.  If  you  could  trace  this 
pipe,  you  would  find  it  connected  with  a  sewer  which 
opens  into  a  large  street  sewer.  Do  you  know  where 
the  sewers  of  your  town  discharge  their  contents! 
In  many  places  the  sewage  is  discharged  into  streams 
or  lakes.  From  what  we  have  already  said  you  can 
see  that  there  are  many  objections  to  this.  Probablj 
the  time  will  come  when  this  method,  except  perhaps 
in  the  largest  cities,  will  be  abandoned.  Many  small 
cities  are  installing  septic  tanks.  The  tank  is  a  large 
receptacle  of  two  or  three  compartments  which 
receives  the  sewage.  It  is  made  of  cement  so  it  is 
absolutely  water  tight.  Bacteria  act  upon  the  mate- 
.rial  changing  it  to  gases  and  liquids  until  most  of  it 


350  STUDIES  IN  SCIENCE 

is  disposed  of.  The  small  amount  of  solid  matter 
known  as  sludge  is  occasionally  removed  from  the 
tanks  and  used  as  a  fertilizer. 

The  need  of  water.  The  human  body  is  composed 
of  different  organs  all  of  which  are  built  up  of  tis- 
sues. There  are  then  several  different  kinds  of  tissue 
in  the  body. 

Muscle  tissue  composes  the  flesh  and  makes  move- 
ments possible. 

Skin  tissue,  also  called  epithelium,  makes  the  out- 
side covering  of  the  body  as  well  as  the  lining  of  the 
mouth  and  other  inner  parts. 

Connective  tissue  is  a  membrane  that  helps  to  hold 
together  the  different  parts  of  the  body,  as  the  bun- 
dles of  muscle  fibers. 

Nerve  tissue  makes  up  the  brain  and  nerves. 

Fat  is  a  tissue  found  in  various  organs.  It  usually 
stores  up  material  for  future  use. 

Gland  tissue  composes  certain  organs  which  make 
secretions  for  use  in  the  body  as  the  saliva  in  the 
mouth  and  the  digestive  fluids  in  the  stomach. 

Bone  and  cartilage  tissue  are  the  solid,  supporting 
parts  of  the  body. 

Now  all  of  these  tissues  are  made  up  of  cells  so 
small  that  you  would  need  a  microscope  to  see  them. 
Each  cell  is  made  of  a  substance  called  protoplasm, 
and  this  is  composed  in  large  part  of  water,  so  that 


WATER  SUPPLY  351 

the  very  material  of  which  the  body  is  composed  is 
dependent  upon  water.  About  three-fourths  of  the 
muscles  are  water,  nine-tenths  of  the  blood  and  nearly 
one-half  of  the  bones  and  cartilage. 

Besides  forming  a  part  of  the  cells  and  tissues, 
water  is  needed  to  soften  all  solid  foods  that  you  eat, 
for  they  must  be  dissolved  and  liquefied  before  they 
can  be  taken  into  the  blood.  Without  sufficient  water 
in  the  alimentary  canal  the  food  moves  along  with 
difficulty  and  indigestion  is  likely  to  follow. 

Oxidation  is  a  process  of  "burning"  which  occurs 
in  the  body  when  the  oxygen  we  breathe  combines 
with  the  food  we  eat.  The  result  of  oxidation  is  heat 
and  energy  for  the  body. 

In  the  process  of  oxidation  in  the  cells  of  the  body 
waste  products  are  produced.  These  must  be  dis- 
solved in  the  watery  part  of  the  blood  and  carried 
to  the  organs  that  throw  them  out  of  the  body  as 
waste  matter.  Hence  the  blood  must  have  a  constant 
supply  of  water.  The  chief  avenues  by  which  water 
with  waste  material  is  given  out  of  the  body  are 
through  the  skin  by  perspiration,  through  the  lungs, 
and  by  way  of  kidneys.  The  amount  given  off  through 
the  skin  by  the  average  healthy  person  should  be  two 
pints  each  day,  from  the  lungs  one  pint,  and  through 
the  kidneys  three  pints. 

An  important  function  of  the  water  taken  into  the 


I 

352  STUDIES  IN  SCIENCE 

body  is  to  flush  out  the  system.    It  takes  out  the  waste 
materials  which  otherwise  develop  poisons. 

The  facts  given  above  suggest  that  if  you  wish  to 
keep  well  you  must  drink  plenty  of  water.  An  adult 
should  drink  about  two  quarts  of  water  a  day.  A 
habit  of  drinking  a  glass  of  water  upon  rising  and 
one  just  before  retiring  is  most  valuable.  Many  of 
the  best  physicians  claim  that  no  harm  comes  from 
drinking  as  much  as  you  desire  while  eating. 

If  there  is  any  question  as  to  whether  water  is  pure 
it  should  be  sterilized.  This  is  done  by  bringing  water 
to  the  boiling  point,  allowing  it  to  boil  a  few  minutes 
and  then  letting  it  cool  When  cool  boil  it  a  second 
time,  put  in  jars  or  bottles,  keep  in  the  ice  box  or 
other  cool  place.  The  second  boiling  kills  any  of 
bacteria  that  may  have  escaped  the  first  time. 

Water  and  care  of  skin.  Water  is  needed  to  keep 
the  skin  in  healthy  condition.  The  small  openings 
from  the  sweat  glands  must  be  kept  open  in  order 
that  there  may  be  a  free  flow  of  perspiration  all  the 
time.  These  may  become  clogged  with  bits  of  solid 
matter  that  are  left  after  the  sweat  evaporates.  Then 
the  oil  glands  connected  with  the  roots  of  the  hairs 
pour  out  on  the  skin  a  small  amount  of  oil.  This  holds 
bits  of  dust  and  may  clog  the  sweat  glands.  Bathing 
is  necessary  to  keep  the  pores  open  and  active.  How 
often  one  needs  to  bathe  depends  upon  the  individual, 


WATER  SUPPLY 

the  very  material  of  which  the  body  is  composed  is 
dependent  upon  water.  About  three-fourths  of  the 
muscles  are  water,  nine-tenths  of  the  blood  and  nearly 
one-half  of  the  bones  and  cartilage. 

Besides  forming  a  part  of  the  cells  and  tissues, 
water  is  needed  to  soften  all  solid  foods  that  you  eat, 
for  they  must  be  dissolved  and  liquefied  before  they 
can  be  taken  into  the  blood.  Without  sufficient  water 
in  the  alimentary  canal  the  food  moves  along  with 
difficulty  and  indigestion  is  likely  to  follow. 

Oxidation  is  a  process  of  " burning "  which  occurs 
in  the  body  when  the  oxygen  we  breathe  combines 
with  the  food  we  eat.  The  result  of  oxidation  is  heat 
and  energy  for  the  body. 

In  the  process  of  oxidation  in  the  cells  of  the  body 
waste  products  are  produced.  These  must  be  dis- 
solved in  the  watery  part  of  the  blood  and  carried 
to  the  organs  that  throw  them  out  of  the  body  as 
waste  matter.  Hence  the  blood  must  have  a  constant 
supply  of  water.  The  chief  avenues  by  which  water 
with  waste  material  is  given  out  of  the  body  are 
through  the  skin  by  perspiration,  through  the  lungs, 
and  by  way  of  kidneys.  The  amount  given  off  through 
the  skin  by  the  average  healthy  person  should  be  two 
pints  each  day,  from  the  lungs  one  pint,  and  through 
the  kidneys  three  pints. 

An  important  function  of  the  water  taken  into  the 


352  STUDIES  IN  SCIENCE 

body  is  to  flush  out  the  system.    It  takes  out  the  waste 
materials  which  otherwise  develop  poisons. 

The  facts  given  above  suggest  that  if  you  wish  to 
keep  well  you  must  drink  plenty  of  water.  An  adult 
should  drink  about  two  quarts  of  water  a  day.  A 
habit  of  drinking  a  glass  of  water  upon  rising  and 
one  just  before  retiring  is  most  valuable.  Many  of 
the  best  physicians  claim  that  no  harm  comes  from 
drinking  as  much  as  you  desire  while  eating. 

If  there  is  any  question  as  to  whether  water  is  pure 
it  should  be  sterilized.  This  is  done  by  bringing  water 
to  the  boiling  point,  allowing  it  to  boil  a  few  minutes 
and  then  letting  it  cool  When  cool  boil  it  a  second 
time,  put  in  jars  or.  bottles,  keep  in  the  ice  box  or 
other  cool  place.  The  second  boiling  kills  any  of 
bacteria  that  may  have  escaped  the  first  time. 

Water  and  care  of  skin.  Water  is  needed  to  keep 
the  skin  in  healthy  condition.  The  small  openings 
from  the  sweat  glands  must  be  kept  open  in  order 
that  there  may  be  a  free  flow  of  perspiration  all  the 
time.  These  may  become  clogged  with  bits  of  solid 
matter  that  are  left  after  the  sweat  evaporates.  Then 
the  oil  glands  connected  with  the  roots  of  the  hairs 
pour  out  on  the  skin  a  small  amount  of  oil.  This  holds 
bits  of  dust  and  may  clog  the  sweat  glands.  Bathing 
is  necessary  to  keep  the  pores  open  and  active.  How 
often  one  needs  to  bathe  depends  upon  the  individual, 


WATER  SUPPLY  353 

but  everyone  should  bathe  often  enough  to  keep  the 
skin  perfectly  clean. 

Cleanliness  is  not  the  only  reason  for  bathing  fre- 
quently. A  bath  stimulates  the  skin  and  in  a  way  the 
whole  body.  Some  people  find  that  a  cold  bath  in 
the  morning  invigorates  them  for  the  entire  day.  Deli- 
cate persons  sometimes  find  that  the  cold  bath  is  too 
stimulating  to  the  heart.  A  cold  bath  should  leave 
one  with  a  warm  glow  all  over  the  body.  This  is 
brought  about  in  part  by  vigorous  rubbing  after  leav- 
ing the  bath.  Just  after  rising  is  the  best  time  for  a 
cold  bath,  or  when  one  is  sweating  and  the  body  is 
very  warm,  though  one  should  use  care  not  to  stay 
in  the  cold  bath  too  long;  one,  two  or  three  minutes 
is  usually  sufficient. 

A  hot  bath  with  soap  is  necessary  to  thoroughly 
cleanse  the  skin.  Hot  baths  should  not  be  taken  in 
cold  weather  if  one  goes  out-of-doors  soon  afterward. 
The  application  of  heat  to  the  skin  causes  the  pores 
to  open  and  the  blood  to  flow  to  the  surface.  While 
in  this  condition  the  body  can  offer  little  resistance  to 
the  cold,  so  you  can  see  why  it  is  a  dangerous  thing 
to  go  out-of-doors  after  taking  a  hot  bath  before  the 
skin  has  had  time  to  recover  its  normal  condition. 
Just  before  going  to  bed  is  the  best  time  for  a  hot  bath. 


CHAPTER  XXI 

FORMS  OF  WATER 

Material.  Several  tin  cups,  a  small  glass  bottle;  a 
flask  with  a  side  delivery  tube,  or  a  rubber  stopper 
with  a  tube  inserted  in  it;  a  measuring  cup  or  grad- 
uate; shallow  pans,  and  a  thermometer. 

In  the  last  chapter  you  found  out  a  number  of  facts 
about  water  as  a  liquid.  But  water  exists  in  other 
forms  that  are  quite  as  interesting. 

Experiment.     Some  facts  about  ice. 

(a)  Fill  a  small  glass  bottle  with  water  and  put 
in  a  stopper.    Set  this  in  a  dish  and  put  it  out-of-doors 
over  night  when  the  weather  is  very  cold. 

(b)  Fill  a  tin  cup  level  full  of  water,  set  in  a  dish 
and  place  out-of-doors  under  similar  conditions. 

Examine  both  bottle  and  cup  the  next  morning. 
What  do  you  find  1  How  do  you  account  for  the  broken 
bottle  ?  What  evidence  have  you  that  the  bottle  broke 
before  all  the  water  was  frozen?  What  has  happened 
to  the  tin  cup?  Is  it  level  full  of  ice!  Which  occupies 
more  space,  water  or  ice? 

Explanation.  Ice,  of  course,  is  water  in  a  solid  form. 
There  is  a  definite  point  of  temperature  at  which 

354 


FORMS  OF  WATER  355 

water  begins  to  solidify.  When  it  cools  down  to  with- 
in a  few  degrees  of  freezing  it  begins  to  expand,  so 
it  must  occupy  more  space.  The  point  at  which  cool- 
ing water  begins  to  expand  is  39°  F.  or  4°  C.  That 
is  why  the  ice  bulges  up  in  the  tin  cup.  The  force 
of  the  expanding  water  broke  the  bottle.  The  fact 
that  you  found  some  water  frozen  in  the  dish  tells  you 
that  all  the  water  had  not  soJidified  when  the  bottle 
broke.  Sometimes  the  force  of  the  expanding  water 
pushes  the  stopper  out  of  the  bottle  instead  of  break- 
ing the  glass. 

Since  water  expands  as  it  freezes,  which  do  you 
think  is  heavier,  ice  or  water? 

Experiment.  Comparative  weight  of  ice  and  water. 
Put  a  chunk  of  ice  at  least  two  inches  thick  into  a 
deep  pan  of  water.  Does  it  sink  or  float!  How  much 
of  it  sinks  down  into  the  water!  If  it  were  heavier 
than  water,  what  would  it  do!  What  would  it  do  if 
it  were  just  the  same  weight  as  water!  If  ice  were 
heavier  than  water,  what  would  happen  when  it  forms 
on  lakes  and  streams! 

Make  a  list  of  all  the  uses  of  ice.  How  is  ice  kept 
for  use  during  hot  weather!  If  possible,  visit  an  ice 
house  and  see  for  yourself  how  it  is  stored  and  kept. 

Explanation.  You  can  readily  see  that  to  keep  ice 
during  the  summer  months  the  temperature  of  the 
ice  house  must  not  go  higher  than  the  melting  point 


356  STUDIES  IN  SCIENCE 

of  ice.  To  keep  it  at  this  low  temperature  the  house 
is  constructed  in  a  way  to  keep  out  the  heat.  That  is, 
non-conductors  are  used  to  prevent  heat  from  enter- 
ing the  house. 

Experiments.  Water  vapor,  (a)  Put  some  water 
into  a  tin  cup  or  pan  and  measure  the  exact  depth  with 
your  ruler.  Set  the  pan  in  a  warm  place  on  the  rad- 
iator, near  the  register,  or  on  the  stove.  After  a  few 
hours  measure  the  water.  Leave  it  in  the  warm  place 
for  twenty-four  hours  and  then  examine  it  again. 
What  has  become  of  the  water? 

(b)  Take  a  flask  having  a  long  delivery  tube  and 
pour  in  water  until  it  is  about  half-full.     Put  in  a 
stopper.     Heat  the  water,  watching  it  carefully  and 
noting  everything  that  happens.    When  the  water  is 
boiling  briskly  what  is  taking  place  at  the  delivery 
tube  ?    Look  closely  at  the  mouth  of  the  tube  and  com- 
pare what  you  find  there  with  what  is  seen  a  little 
farther  out.    Look  in  the  space  above  the  water  in  the 
flask.    Can  you  see  anything!    What  must  be  in  this 
space?    What  is  your  conclusion  as  to  whether  water 
vapor  is  visible  or  invisible? 

(c)  Hold  a  dry,  cold  tin  cup  for  several  minutes 
at  the  mouth  of  the  tube  so  that  the  vapor  will  enter 
the  cup.    What  happens? 

Explanation.  The  water  which  was  in  the  tin  cup 
disappeared  because  the  heat  changed  it  from  a  liquid 


FORMS  OF  WATER  357 

into  a  vapor.  The  vapor  went  off  into  the  air  and  you 
did  not  see  it.  When  any  liquid  changes  into  a  vapor 
we  say  that  it  evaporates. 

The  same  thing  took  place  in  the  flask,  but  because 
more  heat  was  applied  to  it  the  evaporation  took  place 
more  rapidly.  Some  of  it  changed  into  vapor  near 
the  bottom  of  the  flask  and  formed  large  bubbles  which 
came  to  the  surface  of  the  water  and  broke.  This 
process  we  call  boiling. 

The  space  above  the  boiling  water  and  at  the  mouth 
of  the  delivery  tube  seemed  empty  because  water  vapor 
is  invisible.  What  then  is  the  steam  that  you  saw  a 
little  farther  out  from  the  tube?  Your  second  experi- 
ment probably  helped  you  to  solve  that  problem.  When 
you  allowed  the  vapor  to  enter  the  tin  cup  it  was 
changed  back  into  water.  The  steam  that  you  saw 
was  vapor  changing  into  water.  At  first  the  water 
drops  are  so  tiny  that  they  float  in  the  air  making 
the  cloud  of  steam.  When  water  boils  and  changes 
rapidly  into  vapor  we  sometimes  call  the  process  vap- 
orization instead  of  evaporation.  The  process  by 
which  vapor  is  changed  back  into  water  is  called 
condensation. 

Experiments.  What  conditions  influence  the  evap- 
oration of  liquids? 

(a)  Measure  or  weigh  an  exact  amount  of  water 
and  put  it  into  a  shallow  pan.  Put  the  same  amount 


358  STUDIES  IN  SCIENCE 

into  a  pint  cup  and  into  a  pickle  bottle.  Set  the  three 
side  by  side.  The  next  day  measure  or  weigh  the 
amount  left  in  each.  From  which  has  the  greatest 
amount  of  water  evaporated!  The  least!  How  do 
you  account  for  the  difference! 

(b)  Put  equal  amounts  of  water  into  two  tin  cups 
or  tumblers  of  exactly  the  same  shape  and  size.    Put 
one  in  a  warm,  the  other  in  a  cool  place.    After  twenty- 
four  hours  measure  the  water  in  each  and  account  for 
the  difference. 

(c)  Place  equal  amounts  of  water  in  two  tin  cups. 
Set  them  side  by  side  where  there  is  a  draft  of  air. 
If  it  is  not  freezing  weather  set  them  out-of-doors. 
Cover  one  cup  closely  with  a  saucer  or  another  cup.. 
Leave  the  other  open.     Measure  the  water  the.  next 
day  and  explain  the  difference. 

Explanation.  Your  experiments  show  the  following 
truths : 

1.  Water  evaporates  more  rapidly  from  a  large 
exposed  surface  than  from  a  small  one. 

2.  The  higher  the  temperature  the  more  rapid  the 
evaporation. 

3.  Evaporation  is  more  rapid  when  air  moves  over 
the  surface  of  the  water. 

You  may  call  these  the  laws  of  evaporation.  They 
are  just  as  true  of  other  liquids  as  of  water.  All 
liquids,  however,  do  not  evaporate  at  the  same  rate. 


FORMS~OF~  WATER]  359 

You  can  prove  this  by  putting  the  same  amount  each 
of  water,  milk  and  alcohol  into  cups  and  allowing 
them  to  stand  for  a  number  of  hours,  then  noting 
what  is  left  of  each. 

Make  a  list  of  all  the  applications  and  illustrations 
of  the  laws  of  evaporation  that  you  can  think  of. 

Experiment.  What  is  the  effect  of  evaporation  upon 
surrounding  bodies? 

(a)  Dip  your  finger  into  water  and  then  rub  it  on 
the  back  of  your  hand.     Hold  your  hand  up  in  the 
air  waving  it  gently.     How  does  the  wet  spot  feel? 
Touch  your  hand  in  the  same  way  with  alcohol.    What 
happened  to  the  water  and  alcohol! 

(b)  Dip  the  bulb  of  a  thermometer  into  water  or 
alcohol.    Wave  it  gently  back  and  forth  till  the  liquid 
has  all  evaporated.     Does  the  mercury  rise  or  fall! 
What  is  your  answer  to  the  question  at  the  beginning 
of  this  experiment!     Why  do  you  feel  chilly  when 
you  sit  in  damp  clothing!    Why  does  sprinkling  the 
street  on  a  hot  summer  day  cool  the  air! 

Explanation.  When  a  liquid  is  changed  into  a 
vapor  heat  is  used  in  producing  the  change.  The  water 
and  alcohol  used  or  absorbed  some  of  the  heat  from 
your  hand  in  evaporating  or  changing  to  a  vapor  and 
your  hand  felt  cool.  The  heat  of  your  body  is  used 
to  evaporate  the  water  from  damp  clothing.  In  the 
same  way  the  thermometer  was  cooled  by  the  evapora- 


360  STUDIES  IN  SCIENCE 

tion  of  the  liquid  and  the  mercury  went  down.  To 
state  it  briefly,  you  may  say:  Evaporation  has  a  cool- 
ing effect  upon  surrounding  bodies. 

Artificial  ice.  The  manufacture  of  artificial  ice  is 
dependent  upon  the  law  you  have  just  discovered. 
The  ice  plant  has  a  number  of  parts,  but  the  part  in 
which  the  ice  is  made  is  a  huge  tank  filled  with  brine 
through  which  a  coil  of  pipes  extends.  Sitting  in  the 
brine  are  rectangular  cans  filled  with  pure  water  and 


Fig.  66.     Interior  of  tank  room  in  an  ice  factory.    The  brine  tank 
and  the  ammonia  coils  are  under  the  floor. 

tightly  closed.  At  just  the  right  moment  a  valve  is 
opened  allowing  liquid  ammonia  to  enter  the  pipes. 
The  ammonia  at  once  changes  to  vapor  or  gas  so 
rapidly  that  it  absorbs  a  vast  amount  of  heat  from 
the  brine.  The  brine  in  turn  absorbs  heat  from  the 
water  in  the  cans.  This  process  continues  until  the 
water  is  frozen. 


FORMS  OF  WATER  361 

The  regulation  of  heat  in  the  human  body.  The  last 
experiment  will  help  yon  to  understand  how  the  heat 
of  your  own  body  is  kept  regular.  You  probably  know 
that  a  person  who  is  in  good  health  has  a  normal  tem- 
perature of  about  98°  F.  The  heat  of  the  body  is  pro- 
duced by  oxidation  in  the  cells.  The  heat  is  regulated 
in  two  ways. 

1.  By  the  perspiration,  which  is  poured  out  upon 
the  surface  of  the  skin.     The  heat  of  the  body  evap- 
orates this  moisture  and  thus  the  body  is  cooled.    The 
warmer  the  temperature  the  more  rapid  is  the  flow 
of  perspiration  and  the  more  heat  is  used  in  its  evap- 
oration,  hence   the  body  temperature   is   kept   from 
rising  when  one  perspires.     Some  moisture  is   con- 
stantly being  given  off  through  the  skin  even  though 
it  is  not  noticeable. 

2.  The  body  heat  is  also  regulated  by  the  loss  of 
heat  due  to  the  fact  that  the   air  surrounding  the 
body   is   usually    cooler   than   the   body.      The    skin 
radiates  heat  and  the  blood  near  the  surface  becomes 
cool  and  flows  toward  the  interior  of  the  body,  while 
warmer  blood  takes  its  place.    The  more  rapidly  the 
warm  blood  flows   through   the   skin  the  more   heat 
will  be  lost  in  a  given  time. 

Heat  of  vaporization.  The  heat  that  is  used  in 
vaporizing  liquids  is  called  the  heat  of  vaporization. 
This  heat,  does  not  affect  temperature. 


362  STUDIES  IN  SCIENCE 

Experiment.  Fill  a  tin  cup  or  glass  flask  half  full 
of  cold  water.  Set  it  over  an  alcohol  lamp.  Hold  a 
thermometer  in  the  water,  do  not  let  it  touch  the 
bottom,  and  watch  the  mercury.  How  high  does  it 
rise?  What  temperature  is  indicated  when  the  water 
boils!  Keep  the  thermometer  in  the  boiling  water 
several  minutes  or  until  you  are  sure  that  the  mer- 
cury is  not  changing  its  position.  Why  does  not  the 
heat  that  is  passing  into  the  water  continue  to  make 
it  hotter? 

The  heat  at  first  was  used  in  changing  the  tem- 
perature. When  the  water  began  to  boil  all  the  heat 
was  used  in  changing  the  water  into  vapor.  An 
interesting  fact  about  this  heat  of  vaporization  is 
that  when  the  vapor  changes  back  to  water  or  con- 
denses it  gives  out  as  much  heat  as  was  used  in 
changing  it  into  vapor.  This  explains  how  steam 
from  a  boiler  heats  a  radiator.  The  vapor  or  steam 
enters  the  radiator,  cools  and  changes  back  to  water. 
In  this  process  it  gives  out  all  the  heat  that  was 
used  in  vaporizing  it,  and  thus  heats  the  radiator. 

Water  vapor  in  air.  Is  there  any  water  vapor  in 
the  air  of  your  school  room  or  home?  How  do  you 
know?  Think  of  the  frost  that  gathers  on  the  win- 
dows on  a  cold  night  or  the  moisture  that  gathers 
on  the  outside  of  a  pitcher  on  a  warm  summer  day. 

Is  there  water  vapor  in  the  air  out-of-doors?  Where 


FORMS  OP  WATER  363 

does  it  come  from?  How  are  clouds  formed?  What 
causes  rain?  Snow? 

Evaporation  is  constantly  taking  place  from  all 
bodies  and  streams  of  water  as  well  as  from  the  soil. 
When  air  is  warm  it  can  hold  a  great  deal  of  vapor. 
When  a  mass  of  air  is  cooled  the  vapor  begins  to 
condense  and  form  clouds,  just  as  it  did  from  the 
tube  of  the  flask.  If  it  is  cooled  still  more,  the  tiny 
drops  unite  and  form  larger  ones.  Presently  they 
become  so  large  that  they  can  no  longer  float  in  the 
air.  They  fall  and  we  have  a  shower  of  rain. 

Sometimes  the  vapor  becomes  so  cold  that  it  freezes 
or  forms  crystals  before  it  is  condensed  into  water. 
Then  it  falls  in  the  form  of  snow.  When  there  is  a 
light,  fine  snow  catch  some  of  the  crystals  on  a  piece 
of  dark  cloth  or  your  coat  sleeve  and  study  their 
shape.  How  many  different  forms  do  you  find? 
Snow  flakes  are  composed  of  great  masses  of  the 
six-pointed  star  crystals. 


CHAPTER  XXII 

HEAT  AND  HEATING 

Material.  The  heating  plants  of  the  school  and 
home;  candles;  alcohol  lamp  or  Bunsen  burner;  other 
simple  pieces  of  apparatus  suggested  in  connection 
with  experiments. 

Heating  of  the  school  building.  How  is  your  school 
room  heated1?  Look  around  until  you  find  the  source 
of  the  heat.  You  may  find  a  stove,  a  hot  air  register, 
or  a  steam  radiator. 

Experiment.  Study  of  air  currents  in  connection 
with  the  source  of  heat.  Make  a  very  fine  fringe  of 
tissue  paper  about  eight  or  nine  inches  long  and  an 
inch  or  two  wide.  Fasten  this  to  a  long  stick  by 
means  of  a  rubber  band  or  paste.  A  lighted  candle 
or  piece  of  smoking  punk  will  give  more  definite 
results.  Hold  the  fringed  paper  or  candle  close  to 
the  register.  What  happens!  Try  it  in  various  posi- 
tions. Hold  it  close  to  the  ceiling  in  the  vicinity  of 
the  register.  Try  it  in  various  parts  of  the  room. 
What  causes  it  to  move?  What  direction  are  the  air 
currents  moving  with  reference  to  the  register! 

If  there  is  another  register  in  the  room,  make  the 
same  tests.  Is  the  air  coming  in  or  going  out  of  this 

364 


HEAT  AND  HEATING  365 

one  ?  Decide  which  is  the  hot  and  which  is  the  cold 
air  register.  If  you  have  a  stove  or  steam  radiator 
in  the  room,  try  the  same  experiments  with  them. 
Hold  the  fringed  paper  or  candle  above  them,  at  the 
sides,  near  the  top,  near  the  floor.  Hold  it  in  the 
vicinity  of  windows  and  doors.  Open  a  door  about 
twelve  inches;  hold  the  candle  first  near  the  top  of 
the  opening.  Slowly  move  it  downward.  How  do 
you  account  for  what  takes  place?  Try  the  same 
experiment  at  home;  first  with  a  door  opening  into 
another  room;  second  with  one  opening  out-of-doors. 

Explanation.  Your  experiments  have  shown  you 
that  there  are  movements  of  air  in  the  room.  The 
warm  air  is  moving  in  one  direction,  the  cooler  air 
is  moving  in  the  opposite  direction.  The  warm  air 
moves  toward  the  upper  part  of  the  room,  spreads 
out  in  all  directions,  and  then  as  it  cools  slowly 
moves  downward. 

Experiments.  Do  you  find  movements  of  air  around 
any  heated  body? 

Light  a  piece  of  a  candle  about  four  or  five  inches 
tall.  Cut  a  strip  of  blotting  paper  about  half  an 
inch  wide,  or  use  punk.  Light  it,  then  blow  out  the 
flame  and  hold  it  so  that  the  smoke  may  move  with 
the  air  currents  around  the  burning  candle.  Does 
the  smoke  move  toward  or  away  from  the  flame? 
What  is  the  movement  a^Qye  the  flame?  Where  is 


366 


STUDIES  IN  SCIENCE 


the  air  about  the  candle  the  hottest!  Does  the  cool 
air  move  toward  or  away  from  the  heat  of  the  candle  ? 
Explanation.  Currents  of  air  due  to  unequal  heat- 
ing are  called  convection  currents.  Why  does  the 
air  move!  Before  you  try  to  solve  this  problem, 
make  a  study  of  the  source  of  heat.  If  you  trace 
to  its  source  the  hot  air  that  comes  into  the  room 
through  the  register,  you  will  find  it  starts  from  a 
furnace  or  a  heated  room  in  the  basement,  and  is 

carried  upward 
through  a  pipe 
in  the  wall  that 
finally  opens 
into  the  regis- 
ter. 

The  hot  air 
furnace.  Make 
a  careful  study 
of  the  furnace. 
Write  the  names 
of  all  the  parts 
and  try  to  de- 
termine their 
uses.  If  you 
have  a  furnace 
at  home,  study  it  and  report  what  you  find. 

How  large  is  the  fire  pot!     What  is  the  distance 


Fig.    67.      Convection    currents    from    a    hot 
air  furnace.      (After  Barber.) 


HEAT  AND  HEATING  367 

from  the  outside  of  the  jacket  to  the  inside  of  the 
furnace!  What  provision  is  made  for  air  to  enter 
the  jacket!  How  many  cold  air  ducts  are  there? 
Where  do  they  enter  the  jacket?  How  many  hot 
air  ducts  are  there?  To  what  part  of  the  jacket 
are  they  attached?  Investigate  carefully  to  see 
whether  there  is  any  chance  for  air  from  the  base- 
ment to  get  into  the  jacket.  Find  the  air  duct  that 
leaves  the  furnace  and  goes  to  your  room.  If  you 
are  studying  your  home  furnace,  find  the  ducts 
leading  to  the  various  rooms.  Trace  the  cool  air 
ducts  to  the  source  of  fresh  air.  Where  do  you  find 
them?  Do  they  get  their  supply  of  cool  air  from 
the  outside  or  the  inside  of  the  building!  Where 
are  the  cold  air  registers  in  your  home?  Trace  the 
convection  current  from  the  jacket  to  your  room 
and  back  to  the  furnace.  What  provision  is  made  in 
your  home  to  purify  the  air  before  it  returns  to 
the  furnace? 

In  a  large  school  building  you  may  find  that  the 
heated  air  comes  from  a  room  in  the  basement 
instead  of  from  a  jacket.  In  this  kind  of  a  heating 
plant  you  will  find  openings  from  out-of-doors  into 
the  basement.  The  pure  cold  air  passes  over  a  num- 
ber of  hot  steam  pipes;  then  by  means  of  fans  it  is 
forced  into  a  large  room.  From  this  room  the  hot 
air  ducts  carry  it  to  the  various  rooms  of  the  build- 


368  STUDIES  IN  SCIENCE 

ing.  With  such  a  system  you  will  find  that  the  cool, 
impure  air  passes  out  of  the  building  through  ducts 
arranged  for  this  purpose.  You  can  see  these  open- 
ings like  small  chimneys  on  the  top  of  the  building. 

In  homes  heated  by  hot  air  furnaces,  the  cold  air 
registers  are  frequently  placed  in  the  front  hall, 
sometimes  in  the  dining  or  the  living  rooms  near  a 
window.  How  is  fresh  air  supplied  when  this  is 
the  easel 

Jacketed  stove.  If  your  school  room  is  heated  by 
a  jacketed  stove,  study  its  parts  as  suggested  for 
the  furnace.  Find  the  duct  for  the  entrance  of  cool 
air  to  the  jacket,  the  one  for  warm  air  to  leave  the 
jacket. 

How  wide  is  the  air  space  between  the  jacket  and 
fire  bowl?  What  provision  do  you  find  for  the  escape 
of  impure  air?  Test  with  a  thermometer  different 
parts  of  the  room  and  decide  whether  or  not  a  jack- 
eted stove  heats  the  entire  room  evenly. 

If  you  have  an  ordinary  heating  stove,  trace  the 
convection  currents  from  this  to  all  parts  of  the 
room.  Also  test  the  temperature  in  different  parts. 

Experiments.  What  causes  convection  currents  of 
air? 

1.  Stand  a  thermometer  on  the  floor  of  the  room 
for  several  minutes  and  take  the  reading.  Now  place 
it  high  up  in  the  room,  let  it  remain  a  while  and  take 


HEAT  AND  HEATING  369 

the  reading.     Which  position  shows  the  highest  tem- 
perature ? 

2.  Into  a  small  portion  of  hot  water  put  a  few 
drops  of  red  ink.     Fill  a  tumbler  half  full  of  very 
cold  water.     With   a   common   dropper   or  fountain 
pen  filler  put   some  of  the  hot  red  water  into  the 
bottom  of  the  glass  of  cold  water.    What  does  it  do? 

3.  Hold   a   small   piece   of  wood   or   cork   in   the 
bottom  of  a  glass  of  water.     Remove  your  fingers. 
What  happens? 

Why  did  the  piece  of  wood  come  to  the  top  of 
the  water?  Why  did  the  warm  water  come  to  the 
top  and  float  on  the  cold  water?  Why  is  the  warmest 
air  at  the  top  of  the  room?  The  next  experiment 
will  help  to  answer  these  questions. 

4.  Tie  a  piece  of  sheet  rubber  very  securely  over 
the  top  of  a  flask.     Now  heat  the  flask.     Why  does 
the  rubber  bulge   upward?     What  is   in  the   flask? 
You  can  show  the  same  principle  by  another  experi- 
ment.   Hold  the  mouth  of  an  open  flask  under  water. 
With  an  alcohol  or  gas  lamp  heat  the  flask.     Why 
do  bubbles  of  air  come  out  into  the  water? 

Explanation.  You  no  doubt  see  that  the  wood 
floats  on  the  water,  the  warm  water  floats  on  the 
cold,  and  the  warm  air  floats  on  the  cool  air  because 
in  each  case  the  body  that  floats  is  lighter  than  the 
other  one.  Your  experiments  with  the  flask  full  of 


370  STUDIES  IN  SCIENCE 

air  tell  you  that  when  air  is  heated  it  expands  and 
occupies  a  larger  space.  In  the  first  case  it  pushed 
the  sheet  rubber  upward;  in  the  second  it  came  out 
of  the  flask  into  the  water.  If  it  expands  or  spreads 
out,  any  definite  portion  of  it  must,  of  course,  become 
lighter. 

When  the  air  in  the  jacket  of  the  furnace  or  stove 
is  heated  it  expands,  becomes  lighter  and  the  cold 
air  below  floats  or  pushes  it  upward,  through  the 
pipes  or  ducts  and  into  the  room.  In  the  room  the 
same  thing  occurs.  The  warm  air  is  pushed  upward; 
it  cools  and  slowly  drops  down.  There  are  then 
constant  currents  all  over  the  room.  This  continues 
as  long  as  some  air  is  warm  and  light  and  some  cool 
and  heavy.  The  heavy  air  always  moves  toward  the 
light  air,  floating  or  buoying  it  upward.  The  greater 
the  difference  in  temperature  the  more  rapid  is  the 
movement. 

Convection  currents  in  a  chimney.  What  is  the 
purpose  of  the  draft  at  the  lower  front  part  of  a 
stove  or  furnace?  What  causes  the  cold  air  to  enter! 
Trace  the  convection  current  from  the  room  through 
the  stove  and  out  at  the  chimney.  Why  does  the 
opening  of  the  check  draft  at  the  back  of  the  furnace 
keep  the  fire  from  burning  so  rapidly?  Why  does 
closing  the  damper  in  the  pipe  have  the  same  effect? 

Explanation.    When  the  fire  begins  to  burn  and 


HEAT  AND  HEATING  371 

heat  the  air  in  the  stove,  the  cold  air  below  pushes 
in  and  the  heated  air  with  the  smoke  and  gases  from 
the  burning  fuel  are  pushed  up  the  chimney.  There 
must  be  a  fresh  supply  of  air  in  the  stove  or  there 
can  be  no  fire,  so  this  movement  of  convection  cur- 
rents up  the  chimney  helps  to  keep  the  fire  burning. 
When  you  close  the  draft  below  you  shut  out  a  part 
of  the  air  supply,  so  the  fire  cannot  burn  so  rapidly. 
At  the  same  time  you  lessen  the  movement  up  the 
chimney.  When  you  open  the  check  draft  the  cold 
air  rushes  in  and  cools  the  air  in  the  pipe  and  chim- 
ney, thus  causing  the  convection  current  to  move 
more  slowly. 

If  the  lower  part  of  the  furnace  or  stove  becomes 
clogged  with  ashes,  this  cuts  off  the  supply  of  fresh 
air  to  the  fuel  and  retards  the  burning. 

Convection  currents  and  wind.  Have  you  ever 
stood  near  a  bonfire  and  watched  the  strong  current 
carry  light  bits  of  materials  upward?  And  have  you 
felt  the  cold  air  rushing  around  you  toward  the  fire? 
If  you  can  explain  the  reason  for  this  strong  move- 
ment of  air  toward  the  fire,  then  you  understand 
pretty  well  the  cause  of  all  winds  on  the  earth's 
surface  from  a  light  breeze  to  a  raging  tornado.  If 
any  area  on  the  earth's  surface  becomes  heated  more 
than  the  surrounding  areas,  what  will  be  the  effect 
upon  the  air?  Will  the  air  move  away  from  or  toward 


372  STUDIES  IN  SCIENCE 

the  heated  area!  The  greater  the  difference  in  tem- 
perature between  the  two  areas,  the  more  rapidly  will 
the  wind  blow.  Since  the  difference  of  temperature 
really  causes  differences  in  weight  and  pressure  of 
the  air,  we  usually  call  the  area  of  light  air  a  low 
pressure  region,  and  the  area  of  heavy  air  a  high 
pressure  one.  The  wind  always  blows  toward  the 
light  or  low  pressure  region. 

Fuels.  Make  a  list  of  all  the  different  kinds  of 
fuel  that  you  know.  What  is  used  in  your  home  for 
heating  purposes,  for  cooking?  By  reference  to  your 
geography  locate  the  chief  anthracite  or  hard-coal 
fields;  the  bituminous  or  soft  coal  fields;  regions 
where  wood  is  still  used.  Make  a  comparative  study 
of  the  prices  of  different  kinds  of  fuel. 

Experiments.  How  fuels  burn.  Look  into  a  fur- 
nace or  stove  and  watch  the  burning  of  the  fuel. 
What  do  you  see  happening1? 

Take  a  small  splinter  from  a  pine  board.  It  should 
be  eight  or  nine  inches  long  and  not  less  than  half 
an  inch  wide.  A  pointed  piece  split  from  a  lath  is 
good  for  this  experiment.  Hold  the  end  of  it  in  a 
candle  flame  till  it  begins  to  burn.  Watch  it  burn 
a  few  moments,  then  blow  out  the  flame.  What  con- 
tinues to  come  from  the  wood?  Put  a  lighted  match 
in  the  smoke.  What  happens?  Has  the  stick  entirely 
ceased  burning  T7hen  the  flame  is  extinguished?  Blow 


HEAT  AND  HEATING  373 

gently  upon  the  glowing  portion.  Does  it  burn  more 
or  less  brightly?  Which  burns  more  closely  to  the 
wood,  the  flame  or  the  glow?  What  changes  take 
place  in  the  color  of  the  wood  as  it  burns?  What  is 
left  after  the  black  portion  is  burned? 

Explanation.  At  first  the  wood  burned  with  a 
flame.  When  you  extinguished  the  flame  by  blow- 
ing upon  it,  you  found  that  the  stick  still  smoked, 
and  by  applying  a  match  you  could  start  the  flame 
again.  The  smoke  is  made  up  of  gases  from  the  wood 
that  burn  with  a  flame.  The  black  portion  that  is 
left  after  the  gases  are  burned  is  charcoal.  Char- 
coal is  nearly  all  carbon.  The  solid  carbon  burns 
with  a  glow  and  gives  out  much  heat.  The  white 
part  that  is  left  after  the  charcoal  burns  is  called 
ash  or  ashes  and  is  composed  of  minerals  that  will 
not  burn.  If  you  apply  these  observations  to  the 
coal  or  wood,  in  the  stove  or  furnace,  you  find  exactly 
the  same  thing  happening.  The  gases  burn  with  a 
flame,  the  solid  carbon,  charcoal  in  wood,  coke  in 
coal,  burn  with  a  glow. 

Experiments.  What  is  needed  besides  fuel  to  pro- 
duce burning? 

1.  Light  a  fresh  splinter  of  wood  and  when  it  is 
burning  brightly  thrust  it  into  a  tumbler.  Hold 
both  tumbler  and  splinter  sideways.  Does  it  burn 
as  long  as  when  you  hold  it  out  in  the  air? 


374  STUDIES  IN  SCIENCE 

2.  Light  a  candle  that  is  about  two  inches  high, 
set  it  on  the  table  and  turn  a  tumbler  over  it.  Why 
does  the  flame  go  out! 

These  simple  experiments  show  that  you  can  not 
burn  any  material  without  air.  In  fact,  burning  is 
a  chemical  process.  "When  you  held  the  splinter  of 
wood  in  the  flame,  it  became  heated  and  a  portion 
of  it  was  changed  into  gas  or  smoke.  When  there 
was  enough  of  this  heated  gas,  the  oxygen  of  the  air 
began  to  unite  with  it.  This  union  is  called  combus- 
tion, or,  in  everyday  terms,  burning.  The  parts  of 
the  wood  and  the  oxygen  unite  and  form  new  sub- 
stances that  go  off  into  the  air  of  the  room.  When 
the  gas  is  all  burned  out  of  the  wood,  the  solid 
carbon  is  left  and  the  oxygen  continues  to  unite  with 
it.  This  union  is  accompanied  by  a  glow  instead  of 
a  flame.  Oxygen  will  not  unite  with  the  minerals, 
so  when  the  burning  ceases  the  ash  is  left.  When- 
ever anything  is  burning  then,  it  means  that  oxygen 
is  uniting  with  it  and  is  forming  a  new  substance. 
One  of  the  substances  formed  is  carbon  dioxide,  of 
which  you  will  learn  more  in  the  next  chapter. 

Like  all  the  other  elements  of  the  air,  oxygen  is 
invisible.  Nevertheless,  you  can  find  out  something 
about  it  by  an  experiment. 

Experiment.  How  to  make  oxygen.  Mix  together 
equal  portions  of  crushed  potassium  chlorate  and 


HEAT  AND  HEATING 


375 


manganese  dioxide.  Put  two  or  three  spoonfuls  into 
a  test  tube.  Place  a  stopper  in  the  open  end  with  a 
tube  passing  through  it.  Fill  a  few  jars  or  bottles 
with  water  and  invert  them  in  a  pan  of  water.  Now 
heat  the  substance  for  a  few  minutes,  and  place  the 
end  of  the  rubber  tube  into  one  of  the  inverted  bot- 
tles. Note  what  takes  place.  When  all  the  water 
has  been  driven  out,  insert  the  tube  into  another 
bottle.  Continue  this  until  all  the  bottles  are  filled 
with  oxygen. 

Explanation.    You  have  been  generating  oxygen. 
Potassium   chlorate   is   a   compound   made    of   three 


Fig.  68.    Apparatus  for  making  oxygen. 

different  elements  united  into  one  substance.  These 
are  oxygen,  potassium,  and  chlorine.  When  you 
applied  heat  the  compound  was  decomposed  or  broken 
up.  The  oxygen  was  set  free  and  escaped  through 


376  STUDIES  IN  SCIENCE 

the  tube.  The  manganese  dioxide  was  put  in  to  help 
set  the  oxygen  free  at  a  low  temperature.  That  is, 
without  it  you  would  have  to  make  the  potassium 
chlorate  much  hotter  to  release  the  oxygen.  The 
oxygen  passed  through  the  tube  up  into  the  bottle 
of  water.  As  it  is  lighter  than  water  it  went  to  the 
top,  and  as  it  filled  the  bottle  the  water  was  forced 
out. 

How  oxygen  behaves.  Light  a  splinter  of  wood, 
allow  it  to  burn  a  minute.  Note  the  size  and  color 
of  the  flame.  Now,  invert  one  of  the  bottles  contain- 
ing oxygen  and  insert  the  burning  splinter  into  it. 
What  change  takes  place  in  the  burning?  Light 
another  splinter  and  allow  it  to  burn  a  moment. 
Then  blow  out  the  flame.  Insert  the  glowing  splinter 
into  a  bottle  of  oxygen.  What  happens?  Twist  a 
piece  of  wire  around  a  small  bit  of  charcoal.  Set 
the  charcoal  on  fire,  then  lower  it  into  a  bottle  of 
oxygen.  Do  the  same  with  a  candle. 

All  these  experiments  tell  you  that  burning  or 
combustion  takes  place  much  more  rapidly  in  oxygen 
than  in  air.  What  really  happens  is  that  the  oxygen 
unites  with  the  elements  of  the  wood  producing  at 
the  same  time  flame  and  heat.  The  chief  element 
in  wood  is  carbon,  and  the  chief  compound  formed 
by  the  union  of  oxygen  and  wood  is  carbon  dioxide. 

Experiment.     Conduction  of  heat.     Put  the  end  of 


HEAT  AND  HEATING  377 

an  iron  rod  or  poker  into  a  fire  or  the  flame  of  an 
alcohol  lamp.  Remove  it  after  several  minutes.  How 
far  from  the  point  where  it  was  surrounded  by  the 
fire  can  you  detect  heat?  What  must  have  taken 
place  in  the  iron?  Think  of  other  illustrations  which 
show  that  heat  seems  to  travel  slowly  through  a  body. 
Think  of  materials  that  do  not  allow  heat  to  move 
readily  through  them  in  this  way.  If  you  should 
place  a  rod  of  wood  in  the  fire  instead  of  iron,  what 
would  happen?  What  is  the  value  of  wooden  handles 
on  cooking  utensils?  Why  is  woolen  cloth  or  fur 
warmer  than  cotton  or  linen? 

Explanation.  A  substance  like  iron  that  permits 
heat  to  move  rapidly  through  it  from  one  little  par- 
ticle to  another  is  called  a  conductor  of  heat.  Most 
metals  are  good  conductors.  Wood  is  a  non-con- 
ductor. It  may  be  hot  enough  to  burn  and  yet  be 
cool  a  few  inches  from  the  flame. 

Certain  kinds  of  cloth  are  excellent  non-conduc- 
tors of  heat.  Since  your  body  produces  its  own  heat, 
your  clothing  keeps  you  warm  because  it  prevents 
the  heat  from  passing  off  into  the  air.  Wool  and 
fur  are  better  non-conductors  than  cotton.  Linen  is 
cooler  than  any  of  the  others  because  it  is  a  better 
conductor.  Air  is  one  of  the  best  non-conductors. 
It  is  really  the  air  among  the  fibers  of  wool  and  fur 
that  makes  them  such  excellent  non-conductors. 


378 


STUDIES  IN  SCIENCE 


The  fireless  cooker.  The  fireless  cooker  is  a  prac- 
tical application  of  the  principle  of  non-conduction. 
You  may  make  one  of  these  cookers  with  very  little 
expense.  Procure  a  large  tin  coffee  bucket  and 
another  one  three  or  four  inches  less  in  diameter. 
Both  should  have  close  fitting  lids.  Cover  the  small 
pail  all  over  including  the  lid  with  two  layers  of 
asbestos  paper.  Line  the  large  pail  with  the  same 
material.  Put  a  packing  three  or  four  inches  deep 
of  excelsior  in  the  bottom  of  the  large  pail  and  set 
the  small  pail  upon  this.  Now  fill  in  the  space 
between  the  two  pails  with  excelsior,  pushing  it  down 

firmly.  Newspa- 
pers torn  to  shreds 
may  be  used  in- 
stead. Foods  such 
as  rice,  breakfast 
foods,  beans  and 
meats,  may  be 
cooked  by  first 
heating  them  to 
the  boiling  point, 
or,  in  the  case  of 
meat  and  beans, 
cooking  for  about 
fifteen  or  twenty 
minutes,  then  plac- 


Cork 

Fig.   69.     Section  of  a  fireless  cooker, 
s.  Soapstone;  k.  Kettle. 


HEAT  AND  HEATING  379 

ing  the  warm  kettle  or  pan  in  the  cooker.  Cover 
quickly  and  allow  to  stand  from  three  to  five  hours 
or  all  night.  The  non-conducting  substances,  asbestos 
and  excelsior,  retain  the  heat  and  the  food  slowly 
cooks.  Two  boxes  may  be  used  instead  of  tin  pails. 

Experiment.  Radiant  heat.  Heat  the  end  of  an 
iron  rod  or  poker  very  hot.  Now  hold  your  hand 
near  the  heated  portion,  first  beneath,  then  on  the 
sides,  then  above,  and  determine  whether  or  not  you 
can  feel  heat  coming  from  it  in  all  directions.  The 
heat  that  is  given  off  in  straight  lines  from  any  heated 
body  is  called  radiant  heat.  Every  heated  body  gives 
out  radiant  heat  equally  in  all  directions.  An  ordi- 
nary heating  stove  or  a  steam  radiator  heats  the  room 
in  two  ways :  1.  It  heats  the  air  around  it,  which  you 
have  found  causes  convection  currents  that  carry 
the  heat  through  the  room.  2.  It  sends  out  radiant 
heat  in  all  directions.  For  this  reason  objects  in 
the  room  nearest  the  source  of  heat  become  much 
warmer  than  those  farther  away.  You  may  have 
observed  that  steam  and  hot  water  radiators  are 
placed  in  the  coldest  part  of  the  room  so  that  the 
heated  air  will  move  rapidly  to  all  other  parts. 

The  heat  that  comes  from  the  sun  is  radiant  heat. 
The  earth  absorbs  it  and  becomes  warm,  then  it  in 
turn,  especially  at  night  and  in  winter,  cools  by 
radiating  its  heat  into  the  air. 


380 


STUDIES  IN  SCIENCE 


Measuring  temperature.  What  instrument  do  you 
use  to  determine  the  temperature  of  a  room  or  any 
body?  Examine  a  thermometer.  Name  everything 
that  you  find.  What  is  the  highest  number  of  the 
scale?  The  lowest?  How  many  degrees  apart  are 
the  lines  of  the  scale?  What  degree  is  marked 
" Freezing "1  What  is  the  name  of  the  thermometer? 
You  may  find  instead  of  the  name  the  letter  F  or  C. 
The  former  stands  for  Fahrenheit;  the  latter  for 
Centigrade.  The  Fahrenheit  scale  has  180  degrees 
between  the  freezing  point  and  the  boil- 
ing point;  the  Centigrade  scale  only  100 
degrees. 

Put  the  bulb  into  a  dish  of  melting  ice 
or  snow  and  watch  the  mercury.  Describe 
what  happens.  If  it  is  a  Fahrenheit  ther- 
mometer and  has  a  scale  numbered  as  high 
as  212  °;  put  the  ice  cold  water  into  a  tin 
cup  and  hold  a  thermometer  in  it.  Now 
heat  the  water  slowly  until  it  boils.  Do 
not  let  the  thermometer  rest  on  the  bottom 
of  the  cup.  Describe  what  happens.  Why 
does  the  mercury  change  its  position? 

Experiment.  Why  does  the  mercury 
stop  at  a  certain  point  in  the  melting  ice, 
and  at  another  definite  point  in  boiling 
water? 


Fig.  70.   A 
Centigrade 
and  a  Fahr- 
enheit Ther- 
mometer. 


HEAT  AND  HEATING  381 

Fill  a  flask  with  cold  water,  place  in  the  flask  a 
stopper  with  a  small  glass  tube  twelve  or  fifteen 
inches  long  passing  through  it.  Push  the  stopper 
down  until  the  water  stands  a  short  distance  up  in  the 
tube.  Now  slowly  heat  the  flask.  What  happens? 
When  the  water  has  almost  reached  the  top  of  the 
tube,  set  the  flask  in  a  cold  place  and  watch  for 
results.  How  did  heat  affect  the  water?  How  did 
cold  affect  it? 

Try  the  same  experiment  with  some  other  liquids 
as  alcohol,  vinegar,  or  skimmed  milk,  and  compare 
results. 

Explanation.  Your  experiments  show  that  water 
and  other  liquids  expand  when  heated  and  contract 
when  cooled.  Most  thermometers  have  the  tube  filled 
with  mercury;  some  have  alcohol.  These  liquids 
expand  with  heat  and  contract  with  the  cold.  Water 
could  be  used  to  make  a  thermometer,  but  since  it 
freezes  at  a  much  higher  temperature  than  mer- 
cury or  alcohol,  you  can  see  that  it  would  not  be  of 
much  use. 

You  found  in  testing  your  thermometer  that  the 
melting  point  of  ice  or  snow  is  zero  on  the  Centi- 
grade and  thirty-two  on  the  Fahrenheit.  Water 
freezes  at  the  same  temperature  that  ice  melts.  When 
a  pan  of  ice  is  melting  the  temperature  remains  at 
32°  F.  or  0°  C.  until  all  the  ice  is  melted.  Zero  on 


382  STUDIES  IN  SCIENCE 

the  Fahrenheit  scale  marks  the  temperature  at  which 
a  mixture  of  salt  and  ice  freezes. 

You  found  that  water  boiled  at  something  below 
212°  F.  or  100°  C.,  and  as  long  as  you  kept  the  ther- 
mometer in  the  boiling  water  it  did  not  go  any 
higher.  At  sea  level  the  boiling  point  of  water  is 
exactly  212°  F.  and  100°  C.  That  shows  that  no 
matter  how  much  heat  you  put  into  water  after  it 
begins  to  boil,  it  does  not  get  any  hotter.  What  does 
this  heat  do! 

The  refrigerator.  Examine  a  refrigerator.  How 
many  distinct  parts  has  it?  Of  what  material  is  the 
outside  made!  The  inside?  How  wide  a  space  is 
there  between  the  outside  and  the  inside  wall?  What 
is  the  value  of  this  space?  Where  is  the  ice  placed, 
above  or  at  the  side  of  the  food?  How  many  open- 
ings do  you  find  between  the  food  compartment  and 
the  ice  box?  Hold  a  piece  of  smoking  punk  or  paper- 
lighter  both  below  and  above  these  openings  and 
determine  the  direction  of  the  air  currents.  In  what 
direction  is  the  cold  air  moving  from  the  ice?  The 
warm  air  from  the  food?  What  causes  the  convec- 
tion current?  Test  the  temperature  of  the  food  com- 
partment ;  of  the  ice  box.  Compare  with  outside 
temperature.  In  making  the  temperature  test  leave 
the  thermometer  several  minutes  in  each  compart- 
ment of  the  refrigerator  with  the  doors  all  closed, 


HEAT  AND  HEATING  383 

then  read  it  quickly  before  you  remove  it  from  the 
compartment. 

Explanation.  The  refrigerator  illustrates  several 
of  the  principles  you  have  been  studying.  The  space 
between  the  inner  and  outer  wall  is  filled  with  some 
kind  of  non-conducting  material  that  prevents  some 
heat  from  entering  the  refrigerator.  The  air  in  the 
space  is  itself  a  poor  conductor  of  heat.  The  ther- 
mometer told  you  that  the  air  leaving  the  ice  box 
is  cooler  than  that  in  the  food  compartment.  It  moves 
downward  at  the  central  opening  just  under  the  ice, 
while  the  warmer  air  moves  upward  through  the 
side  openings.  This  warm  air  passes  over  the  ice, 
is  again  cooled,  and  again  drops  down  into  the  food 
compartment.  The  heat  in  the  warm  air  is  used  to 
melt  the  ice.  This  is  the  chief  reason  that  it  cools 
so  quickly. 

Your  refrigerator  may  have  an  opening  at  each 
side  instead  of  one  in  the  middle.  In  that  case  the 
cold  air  goes  down  one  side  and  the  warmer  air  up 
the  other.  Some  refrigerators  have  the  ice  box  at 
the  side  instead  of  at  the  top.  The  openings  are 
arranged  so  that  the  cold  air  moves  downward  on 
the  side  toward  the  ice  and  upward  on  the  other  side. 

Making  ice  cream.  If  you  have  ever  made  ice 
cream  you  know  that  ice  and  salt  are  placed  in  the 
freezer  around  the  can  that  holds  the  cream.  The 


384  STUDIES  IN  SCIENCE 

ice  begins  to  melt  and  the  salt  dissolves  and  soon 
the  cream  is  frozen.  Ice  in  the  process  of  melting 
or  changing  to  water  absorbs  heat  just  as  water 
changing  to  vapor  does.  In  the  freezer  the  melting  ice 
uses  up  heat  from  the  cream,  but  it  probably  would 
not  cool  it  enough  to  freeze  if  it  were  not  for  the  salt, 
which  causes  the  ice  to  melt  more  rapidly.  The 
temperature  of  a  mixture  of  salt  and  ice  is  much 
lower  than  that  of  melting  ice  alone,  as  you  have 
already  discovered  from  your  study  of  the  Fahren- 
heit thermometer.  The  heat  absorbed  by  the  mix- 
ture soon  cools  the  cream  down  to  the  freezing  point. 


CHAPTER  XXIII 

ATE 

What  air  is.  You  can  not  study  the  heating  of 
the  home  without  at  the  same  time  giving  some  atten- 
tion to  air  and  ventilation.  You  have  already  found 
that  heating  buildings  by  any  system  depends  largely 
upon  air  currents. 

What  is  air?  It  is  not  easy  to  answer  this  ques- 
tion. In  the  first  place,  air  is  invisible.  You  cannot 
see  it  but  you  can  feel  it  rushing  against  you  when 
the  wind  blows,  or  when  you  run  or  ride  rapidly. 
It  fills  every  space  on  the  earth  that  is  not  occupied 
by  something  else.  If  you  pour  water  out  of  a 
pitcher,  air  immediately  rushes  in  and  fills  up  the 
space.  When  you  say  a  cup,  a  box,  or  a  bottle  is 
empty,  you  really  mean  that  it  has  nothing  in  it  but 
air.  Air  fills  the  small  spaces  in  the  soil  when  they 
are  not  full  of  water.  Even  the  water  in  streams, 
lakes,  and  the  ocean  has  air  mixed  with  it.  If  it 
were  not  for  this,  fish  and  other  water  animals  could 
not  exist.  Air  surrounds  the  entire  earth  like  a  great 
envelope,  extending  outward  at  least  100  miles,  pos- 

385 


386  STUDIES  IN  SCIENCE 

sibly  more.     We  usually  speak  of  this   envelope   of 
air  as  the  atmosphere. 

Air  is  a  mixture  of  several  gases.  You  know 
already  what  some  of  them  are.  You  remember  that 
the  part  of  the  air  that  unites  with  wood  and  other 
materials  in  burning  is  oxygen.  This  is  the  most 
important  gas  in  the  air.  All  animals  and  plants  as 
well  as  fires  are  dependent  upon  it  for  existence. 
About  twenty  per  cent  of  pure  air  is  oxygen. 

You  have  also  found  that  there  is  water  vapor 
in  the  air.  It  contains  three  other  gases.  Nitrogen 
constitutes  nearly  seventy-eight  per  cent  of  the  entire 
bulk  of  air.  Then  there  is  some  argon  and  a  small 
amount  of  carbon  dioxide.  Beside  the  gases  air 
always  contains  a  great  number  of  floating  dust  par- 
ticles. 

The  proportion  of  the  gases  in  the  air  varies  from 
time  to  time,  and  the  amount  of  water  vapor  varies 
greatly.  There  is  always  a  much  larger  per  cent 
preceding  rainstorms. 

The  air  that  you  exhale  has  more  carbon  dioxide 
and  less  oxygen  than  the  air  you  inhale.  Exhaled  air 
contains  about  4  per  cent  carbon  dioxide  and  16  per 
cent  oxygen. 

The  different  substances  in  pure  air,  with  the  ap- 
proximate amount  of  each,  is  shown  in  the  following 
table : 


AIR  387 

Per  cent, 
of  volume 

Nitrogen 77.42 

Oxygen  20.77 

Carbon  dioxide 0.03 

Argon  and  other  gases 0.93 

Water  vapor    0.85 


100.00 


Facts  about  air.  There  are  some  other  facts  con- 
cerning air  that  you  can  find  out  by  experiment. 
You  will  need  a  tumbler,  a  tall  wide-mouthed  bottle, 
a  tube  about  fifteen  inches  long  with  a  stopper  in 
one  end;  a  tube  five  or  six  feet  long;  another  of  small 
diameter  about  thirty  inches  long. 

Experiment  1.  Fill  the  tumbler  with  water.  Hold 
your  hand  over  the  mouth  and  invert  the  tumbler 
in  a  pan  of  water  with  the  mouth  just  under  the 
surface. 

Experiment  2.  Try  the  same  experiment  with  the 
tall  bottle  and  the  long  tube.  What  holds  the  water 
up  in  the  vessels? 

Experiment  3.  Fill  the  15-inch  tube  and  invert 
as  you  did  the  tumbler  and  bottle.  While  you  are 
holding  it  remove  the  stopper  from  the  upper  end. 
What  happens?  Why  did  the  water  flow  out? 

Explanation.  The  last  experiment  will  help  you 
to  answer  the  question  raised  by  the  other  two.  When 
you  removed  the  stopper  the  air  above  the  tube 


388  STUDIES  IN  SCIENCE 

pushed  the  water  down  into  the  pan.  The  air  is 
pushing  with  the  same  force  upon  the  surface  of  the 
water  in  the  pan.  As  long  as  the  tube  was  closed 
at  the  top  the  air  could  not  exert  any  direct  force 
upon  the  water,  so  the  pressure  of  the  air  upon  the 
surface  of  the  water  in  the  pan  held  the  column  of 
water  up  in  the  tube.  If  this  is  true,  then  air  must 
have  weight.  If  you  had  an  air-pump  and  a  bottle 
with  a  stopcock,  you  could  prove  by  experiment  that 
this  is  true.  Air  does  not  weigh  very  much.  A  cubic 
foot  of  air  weighs  about  534  grains.  But  when  a 
column  of  air  several  hundred  feet  high  presses  down 
upon  the  earth,  or  upon  bodies  on  the  earth,  even 
this  relatively  light  weight  gives  it  considerable  force 
or  pressure.  Scientists  have  found  by  experiment 
that  the  pressure  of  the  air  near  the  level  of.  the  sea 
is  about  15  pounds  per  square  inch. 

Experiment  4.  Do  you  think  you  could  find  a  tube 
so  long  that  the  air  pressure  could  not  hold  the  water 
to  the  top  of  it?  You  can  answer  this  question  by 
using  mercury  instead  of  water.  Fill  the  small  tube 
full  of  mercury  and  invert  it  in  a  dish  of  mercury. 
What  happens?  Why  did  some  of  the  mercury  flow 
out?  Why  did  it  stop  after  a  certain  amount  had 
flowed  out?  With  a  meter  stick  or  yard  ruler  meas- 
ure the  height  of  the  column  of  mercury  in  the 
tube.  Since  mercury  is  13%  times  as  heavy  as  water, 


AIR 


389 


how  high  a  column  of  water  would  the  air  hold  up? 
How  high  is  the  column  of  air  that  is  balancing  the 
column  of  mercury!  Fasten  the  tube  of  mercury 
to  the  rod  of  a  burette  stand  or  some  other  support 
and  allow  it  to  stand  in  the  room  for  a  number  of 
days.  Measure  the  column  twice 
every  day.  Can  you  explain  why  it 
varies  !  What  name  may  you  give  to 
this  simple  instrument  that  enables 
you  to  measure  air  pressure! 

Explanation.  Some  of  the  mer- 
cury flowed  out  of  the  tube  into 
the  dish  because  the  air  pressure 
was  not  sufficient  to  hold  it  all  up. 
When  the  weight  of  the  column  of 
air  and  of  the  mercury  were  just 
the  same  the  mercury  ceased  to  flow 
out.  You  can  think  of  the  air  and 
mercury  columns  as  a  pair  of  bal- 
ances with  the  weight  on  each  side 
exactly  equal.  The  column  of  air 
has  exactly  the  same  cross-section 
area  as  that  of  the  mercury,  but  it 
is  as  high  as  the  air  extends  above  the  earth. 
Fig.  65. 

Uses  of  the  barometer.    If  something  causes  the 
air  to  become  lighter,  the  mercury  goes  down.     If 


Air  sup- 
ports a  column  of 
mercury  30  inches;  a 
column  of  water  34 
feet. 


See 


390 


STUDIES  IN  SCIENCE 


the  air  becomes  heavier,  the  mercury  rises  or  is 
pushed  up.  You  have  really  made  a  simple  baro- 
meter with  which  you  may  measure  the 
pressure  of  the  air.  If  there  is  a  barome- 
ter in  the  building,  study  it  and  compare 
with  your  simple  one.  You  will  find  that 
it  is  made  on  exactly  the  same  principle. 
It  has,  however,  a  fixed  scale  that  enables 
you  to  read  the  height  of  the  column  very 
accurately. 

You  probably  wonder  why  the  air  pres- 
sure varies  from  day  to  day.  The  chief 
cause  of  variation  is  due  to  different 
amounts  of  water  vapor.  Water  vapor  is 
lighter  than  the  other  gases  of  the  air. 
When  there  is  a  large  percentage  of  it 
present,  the  air  is  light.  When  there  is 
little  moisture,  the  air  is  heavy.  A  low 
barometer  then  indicates  more  moisture 
and  the  likelihood  of  storms ;  while  a  high 
barometer  indicates  a  dry  atmosphere  and 
fair  weather. 

Since  air  pressure  is  due  to  the  weight 
of  the  air,  where  will  air  on  the  earth 
exert  the  greatest  pressure!  You  can 
think  this  out  by  placing  all  your  books 
in  a  pile  on  your  desk.  Which  one  of  the 


Fig.  72.  A 
standard  mer- 
curial barom- 
eter. 


AIR 


391 


books  has  the  greatest  pressure  upon  it  I  In  pre- 
cisely the  same  way  the  lowest  part  of  the  air  has 
the  most  pressure,  because  of  the  weight  of  all  the 
rest  of  the  air  above  it.  If  you  should  take  a  baro- 
meter to  the  top  of  a  high  mountain,  would  the  mer- 
cury go  up  or  down?  Why?  If  you  lived  one  thou- 
sand feet  above  sea  level,  and  you  should  take  a  baro- 
meter down  to  the  sea,  would  the  mercury  go  up  or 
down?  Why?  Scientists  know  exactly  how  much 
the  barometer  falls  with  each  foot  of  ascent  at  a 
given  temperature,  so  a  barometer  may  be  used  to 
determine  how  far 
above  sea  level  any 
point  is  located. 

Air  pressure  and 
pumps.  Place  one  end 
of  a  glass  tube  open  at 
both  ends  into  a  glass 
of  water.  Slowly  suck 
the  air  from  the  tube. 
What  happens?  What 


Fig.  73.     A  common  suction  pump 
showing  piston,  valves,  etc. 


forces  the  water  into  the  tube?  You  no  doubt  see 
that  as  you  remove  the  air  from  the  tube  the  down- 
ward pressure  on  the  water  in  the  glass  pushes  the 
water  upward  in  the  tube.  This  illustrates  in  a  very 
simple  way  what  happens  when  you  pump  water  with 
a  common  suction  pump. 


392  STUDIES  IN  SCIENCE 

Study  the  parts  of  an  ordinary  pump.  To  what 
is  the  handle  attached?  What  does  the  rod  do  as 
you  work  the  handle?  If  possible,  take  the  pump 
apart  and  find  what  is  fastened  to  the  rod  -at  the 
lower  end. 

Making  a  pump.  If  you  are  skillful,  you  can  make 
a  miniature  pump  that  will  work  exactly  as  the  real 
one  does. 

Procure  a  straight  lamp  chimney,  two  pieces  of 
cork,  a  glass  tube,  some  pieces  of  thin  leather  and 
some  wire.  Make  a  hole  in  one  piece  of  cork  and 
fit  the  piece  of  glass  tubing  into  this  hole  so  that 
the  tubing  will  come  just  to  the  surface  of  the  cork. 
Over  the  hole  place  a  thin  piece  of  leather,  fasten  it 
at  one  end  with  a  small  tack  or  pin.  This  cork 
should  fit  closely  into  the  lower  end  of  the  chimney. 
Make  a  similar  hole  in  the  second  cork  and  fasten 
a  piece  of  leather  in  the  same  way  over  the  opening 
at  the  lower  end.  Fasten  a  piece  of  wire  into  the 
upper  part  of  the  cork.  To  this  fasten  a  heavier  wire. 
This  cork  should  be  trimmed  off  so  that  it  will  move 
easily  up  and  down  in  the  chimney,  or  it  may  be 
wrapped  with  thin  muslin  so  that  it  will  fit  the  chim- 
ney snugly. 

You  now  have  all  the  parts  of  a  simple  suction 
pump.  The  chimney  is  the  pump  barrel  or  cylinder. 
The  cork  that  moves  up  and  down  is  the  piston  and 


AIR  393 

the  wire  with  which  you  move  it  is  the  piston  rod. 
The  tube  at  the  lower  end  is  the  suction  pipe.  The 
pieces  of  leather  covering  the  openings  serve  as  valves 
that  open  or  close. 

Place  the  glass  tube  of  the  pump  in  a  dish  of 
water.  Pull  the  piston  upward.  What  happens? 
Now  move  the  piston  downward  and  watch.  What 
effect  did  the  lifting  of  the  piston  in  the  first  place 
have  upon  the  air  in  the  cylinder? 

A  portion  of  the  air  was  lifted  up  with  the  cylin- 
der; hence  the  air  pressure  upon  the  water  in  the 
pan  was  greater  than  that  in  the  cylinder  and  pushed 
the  water  upward  through  the  lower  valve.  Watch 
carefully  everything  that  happens  when  you  move 
the  piston  downward.  Why  does  the  water  move 
upward  through  the  upper  valve  and  why  does  the 
lower  valve  remain  closed? 

The  pressure  now  is  due  to  the  force  with  which 
you  are  pushing  the  piston  downward.  This  force 
of  the  water  pushes  upon  the  lower  valve  and  holds 
it  down,  but  the  same  force  causes  the  water  to  push 
upward  against  the  lower  part  of  the  piston,  which 
opens  the  upper  valve  arid  gives  the  water  a  chance 
to  rush  through  and  fill  the  cylinder.  This  is  exactly 
what  happens  when  you  pump  water  from  a  well. 
You  can  see  the  piston  rod  which  is  attached  to  the 
handle  moving  up  and  down  in  the  cylinder.  The 


394  STUDIES  IN  SCIENCE 

valves  are  at  the  lower  part.  The  pipe  extends  down 
into  the  water  of  the  well. 

There  are  some  other  kinds  of  pumps  but  all  of 
them  are  dependent  upon  air  pressure  to  do  their 
work. 

The  vacuum  cleaner.  The  vacuum  cleaner  used  in 
the  home  is  a  good  illustration  of  air  doing  work. 
Study  a  vacuum  cleaner.  What  are  the  main  parts! 
How  does  it  succeed  in  taking  the  dust  out  of 
rugs,  etc.! 

You  find  three  chief  parts  to  any  vacuum  cleaner 
whether  it  is  large  or  small,  whether  it  is  run  by 
hand  or  some  other  power. 

1.  A  tube  or  barrel. 

2.  A  piston  that  works  in  the  tube. 

3.  A  nozzle,  with  a  small  opening,  by  which  the 
suction  as  it  passes  over  the  surface  of  objects  is 
increased. 

When  you  move  the  piston  the  air  in  the  tube  is 
pushed  upward  and  escapes  through  a  small  hole  in 
the  upper  part  of  the  tube.  The  tube  below  the 
piston  is  almost  emptied  of  air,  so  the  heavier  out- 
side air  rushes  in  carrying  dust  and  other  bits  of 
dirt  with  it.  The  nozzle  simply  defines  a  definite 
space  from  which  the  air  rushes  in  and  from  which 
all  dust  and  dirt  are  soon  cleared. 

Other  uses  of  air.    Think  of  other  ways  in  which 


AIR  395 

air  is  controlled  by  man  so  as  to  aid  in  doing  work. 
Among  these  is  the  windmill  which  is  constructed 
in  a  way  to  make  air  pump  water.  If  you  have  a 
bicycle,  you  pump  the  tire  full  of  air.  Tires  of  auto- 
mobiles are  filled  with  compressed  air.  Compressed 
air  is  used  in  some  places  to  run  machinery. 

Air  and  health.  All  life  is  dependent  upon  air.  It 
is  of  the  greatest  importance  to  have  plenty  of  pure 
air  in  our  homes  and  schools.  Pure  air  contains  20 
per  cent  of  oxygen,  and  does  not  have  many  dust 
particles  floating  around  in  it.  The  dust  particles 
in  air  are  of  two  kinds,  dead  dust  and  living  dust. 
The  former  consists  of  bits  of  soil,  ash,  lint  from 
clothing,  and  the  like.  This  in  itself  is  not  really 
harmful  unless  there  is  a  vast  amount  of  it  present. 
In  that  case  it  irritates  the  mucous  membrane  of  the 
nose,  throat  and  lungs,  and  thus  weakens  their  re- 
sistance against  disease  germs. 

Live  dust  consists  of  living  organisms  so  small 
and  light  that  they  easily  float  about  in  the  air  by 
themselves,  or  more  often  upon  the  dead  dust  parti- 
cles. They  consist  of  spores  of  mold  and  other  lower 
plant  forms,  and  bacteria  of  various  kinds,  some 
harmless  but  others  that  produce  human  diseases. 

Air  in  houses  where  people  are  living  and  work- 
ing and  where  fires  are  burning  is  likely  to  become 
very  impure  unless  care  is  taken  to  see  that  fresh 
air  has  a  chance  to  come  in. 


396  STUDIES  IN  SCIENCE 

What  provision  for  ventilation  is  made  in  con- 
nection with  the  heating  of  your  home  or  school 
room?  Is  the  warm  air  that  enters  the  room  through 
the  register  pure?  You  can  answer  this  question 
by  going  back  to  the  furnace  and  tracing  the  cold 
air  duct  to  its  source.  Does  the  air  come  from  out- 
of-doors  or  from  some  room  in  the  house?  In  many 
homes  you  find  the  cold  air  register  in  the  hall. 
When  this  is  the  case  great  care  should  be  taken 
to  see  that  the  air  in  the  hall  is  kept  as  pure  as  pos- 
sible. This  can  be  done  by  keeping  the  hall  window 
slightly  open.  When  the  cold  air  register  is  in  the 
living  or  dining  room,  these  rooms  should  be  flushed 
with  fresh  air  several  times  during  the  day  by  throw- 
ing open  windows  and  doors. 

Homes  heated  by  hot  water,  steam  or  stoves  are 
usually  ventilated  by  means  of  doors  and  windows. 
A  few  buildings  have  special  air  shafts  through 
which  the  impure  air  may  be  carried  out  of  the  rooms. 
In  ventilating  any  room  you  must  consider  two  things : 
1.  A  place  for  the  entrance  of  pure  air.  2.  A  place 
for  the  exit  of  impure  air.  This  means  that  there 
will  be  currents  of  air  in  the  room.  In  fact,  no  room 
can  be  ventilated  unless  the  air  is  in  constant  motion. 
If  an  opening  is  provided  for  the  escape  of  impure 
air,  plenty  of  fresh  air  will  come  in  around  doors  and 
windows.  An  open  grate  or  fireplace,  though  very 


AIR  397 

wasteful  of  heat,  provides  one  of  the  best  means  of 
ventilating  homes.  The  burned  gases  with  air  from 
the  room  pass  up  the  chimney.  Fresh,  outside  air 
pushes  into  the  room  through  every  crack  and  crevice. 
A  stove,  though  not  so  good  as  a  grate,  serves  some- 
what the  same  purpose. 

Experiment.    What    happens    when   you   breathe? 

You  probably  know  that  your  breathing  organs  con- 
sist of  the  nostrils,  trachea  or  windpipe,  and  lungs. 
Place  your  hands  on  the  upper  part  of  your  chest 
with  the  tips  of  the  second  fingers  touching  each 
other.  Now  inhale,  filling  your  lungs.  Then  exhale. 
Note  what  takes  place  in  each  case.  Place  your  hands 
at  your  sides  just  above  the  waist  line  with  the 
finger  tips  touching  as  before.  Inhale  and  exhale, 
watching  the  movements.  Watch  the  shoulders  of 
some  of  your  classmates,  noting  the  breathing  move- 
ments. 

Respiration.  These  observations  show  that  when 
you  inhale  the  chest  moves  outward  and  upward,  the 
ribs  outward  and  the  shoulders  upward.  The  dia- 
phragm, which  is  a  muscular  partition  between  the 
chest  cavity  and  the  abdominal  cavity,  moves  down- 
ward. All  these  movements  make  the  chest  cavity 
larger,  and,  since  the  air  that  is  in  the  lungs  spreads 
out  to  fill  the  increased  space,  the  air  pressure  in  the 
lungs  is  less  than  that  outside,  so  the  air  rushes  in  till 


398 


STUDIES  IN  SCIENCE 


the  lungs  are  filled  with  air  of  the  same  pressure  as 
that  outside.  When  you  exhale,  the  ribs  move  inward, 
the  chest  and  shoulders  downward,  so  that  the  cavity 


bi 


Fig.  74.     L,  Front  view  of  the  larynx;  T,  Trachea;  B,  Bronchial 
tubes;  bt,  Bronchioles. 

is  made  smaller  and  the  air  is  pressed  or  pushed  out 
through  the  trachea  and  the  nostrils. 

In  the  iungs  the  air  that  is  inhaled  mixes  with 


AIR  399 

the  air  that  is  already  there  and  in  this  way  a  fresh 
supply  of  oxygen  is  brought  in.  The  oxygen,  how- 
ever, to  be  of  use  must  not  remain  in  the  lungs.  It 
passes  through  the  thin  walls  of  little  air  sacs  in  the 
lungs,  then  through  the  walls  of  the  small  blood 
tubes  into  the  blood. 

If  you  could  see  the  structure  of  a  lung,  you  would 
find  that  the  trachea  divides  into  two  branches  called 
bronchi,  one  is  a  bronchus.  These  divide  and  sub- 
divide into  smaller  and  smaller  tubes  until  finally 
each  one  ends  in  a  tiny  air  sac  made  of  thin  mem- 
brane. It  is  from  these  little  sacs  that  the  oxygen 
passes  into  the  blood.  See  Fig.  74. 

The  blood  is  composed  of  a  thin  watery  fluid  called 
plasma,  and  a  great  number  of  tiny  floating  bodies 
in  this  called  corpuscles.  Most  of  the  corpuscles  are 
reddish  in  color,  a  few  larger  ones  are  white.  The 
white  corpuscles  are  the  purifiers  of  the  body. 
They  carry  off  and  destroy  disease  germs  and  in 
other  ways  keep  the  body  in  good  condition.  The 
red  corpuscles  absorb  oxygen  from  the  air  in  the  air 
sacs  of  the  lungs  and  carry  it  to  all  parts  of  the  body 
where  it  is  needed.  It  is  needed  wherever  there  is  work 
of  any  kind  going  on,  or  where  heat  is  produced. 
To  do  its  work,  the  oxygen  leaves  the  red  corpuscles 
of  the  blood  and  enters  the  cells  of  the  tissues.  Here 
it  unites  with  the  carbon  that  the  cells  have  absorbed 


400  STUDIES  IN  SCIENCE 

from  the  food.  The  result  of  this  union  is  that  energy 
is  produced  and  heat  is  generated.  You  see  that 
heat  is  produced  in  precisely  the  same  way  as  when 
carbon  from  wood  or  coal  unites  with  oxygen  in  a 
stove  or  furnace,  only  in  the  body  there  is  no  accom- 
panying flame  or  light,  so  we  call  the  process  oxida- 
tion instead  of  combustion.  The  union  of  the  oxygen 
and  carbon  produces  a  compound  called  carbon 
dioxide,  which  is  a  waste  product.  This  is  taken  into 
the  lymph,  then  into  the  plasma  of  the  blood  and 
carried  back  to  the  lungs  where  it  passes  into  the  air 
sacs  and  is  carried  out  with  the  breath. 

Circulation.  The  relation  of  the  blood  and  oxygen 
in  the  body  is  most  interesting.  All  the  blood  from 
the  lungs,  with  its  load  of  oxygen,  is  collected  into 
four  large  tubes  or  blood  vessels  called  the  pulmon- 
ary veins,  which  enter  the  left  auricle  of  the  heart. 
The  heart  has  four  compartments  or  chambers  known 
as  the  right  and  left  auricles  and  the  right  and  left 
ventricles.  The  blood  that  enters  the  left  auricle  is 
what  is  ordinarily  called  pure  blood;  that  is,  it  has 
a  large  amount  of  oxygen  in  the  red  corpuscles.  From 
the  left  auricle  the  blood  flows  downward  into  the 
left  ventricle.  This  ventricle  contracts.  That  is,  the 
walls  grow  thicker,  come  close  together,  and  squeeze 
the  blood  out.  It  is  prevented  from  going  back  into 
the  auricle  by  valves  between  the  two  chambers  which 


AIR  401 

are  closed  by  the  force  of  the  blood  flowing  against 
them  as  the  ventricle  contracts.  These  valves  act  on 
the  same  principle  as  the  valve  in  the  ordinary  pump. 
The  blood  is  pushed  into  a  large  thick-walled  artery 
called  the  aorta.  From  here  it  goes  all  over  the 
body  in  tubes  which  branch  out  from  the  aorta.  All 
these  tubes  are  called  arteries. 

Put  your  fingers  lightly  on  the  sides  of  your  throat. 
You  can  feel  the  pulsation  of  the  two  arteries  which 
go  to  the  head.  At  the  wrist  you  can  feel  one  of  the 
branches  that  extends  down  the  arm.  The  blood 
from  the  heart  does  not  flow  into  the  aorta  in  a  steady 
stream,  but  in  one  impulse  after  another.  The  ven- 
tricle contracts  and  forces  the  blood  out,  then  it 
relaxes  and  there  is  a  pause.  The  blood  would  flow 
back  into  the  heart  at  this  time  if  there  were  not 
valves  in  the  aorta  to  prevent  it.  This  contraction 
and  relaxation  of  the  heart  is  the  beat  that  you  can 
feel.  It  also  causes  the  pulse  of  the  arteries,  for  the 
walls  are  elastic  and  expand  and  relax  with  the 
movement  of  the  blood  from  the  heart. 

The  arteries  grow  smaller  and  smaller  toward  the 
extremities  of  the  body.  Finally  they  break  up  into 
very  small  tubes  called  capillaries.  These  are  so 
numerous  that  you  can  not  pierce  your  finger  or  any 
other  part  of  the  body  with  the  finest  needle  without 
breaking  several  of  them.  It  is  in  the  capillaries 


402  STUDIES  IN  SCIENCE 

that  the  oxygen  passes  out  of  the  corpuscles  into 
the  cells.  It  is  here,  too,  that  the  food  which  is  car- 
ried in  the  blood  flows  out  to  feed  the  cells. 

The  capillaries  unite  and  form  small  veins;  these 
unite  again  and  again,  growing  larger  and  larger 
until  in  the  inner  portion  of  the  body  there  are  very 
large  veins.  You  can  see  the  veins  and  their  branches 
near  the  surface  in  your  hands  and  arms.  At  last 
all  the  veins  in  the  upper  portion  of  the  body  unite 
into  one  large  vein  near  the  heart,  and  all  in  the 
lower  part  unite  into  another  large  vein.  The  upper 
one  is  called  the  descending  vena  cava,  the  lower 
one  the  ascending  vena  cava.  These  empty  the  blood 
into  the  right  auricle  of  the  heart.  From  here  the 
blood  goes  into  the  right  ventricle.  The  right  ven- 
tricle contracts  at  the  same  time  the  left  one  does 
and  sends  the  blood  through  the  large  pulmonary 
artery  to  the  lungs.  This  blood,  since  it  comes  from 
all  over  the  body,  contains  a  large  amount  of  waste 
products,  especially  carbon  dioxide,  which  is  given 
up  to  the  air  in  the  lungs  and  carried  out  with  the 
breath. 

Hygiene  of  breathing.  From  your  observation  of 
breathing  movements  it  must  be  evident  that  if  you 
fill  all  the  air  spaces  in  your  lungs  you  must  enlarge 
the  chest  cavity  sufficiently  to  allow  every  portion 
of  the  lungs  to  expand.  If  clothing  is  worn  too  tight 


AIR  403 

about  the  waist,  the  movements  of  the  ribs  and  dia- 
phragm may  be  impeded  and  healthful  breathing 
prevented.  Out-door  exercise  causes  rapid  breath- 
ing and  fills  the  lungs  with  pure  air.  If  you  do  not 
take  much  out-door  exercise  it  is  a  good  plan  to 
practice  deep  breathing  at  least  twice  each  day.  In 
the  morning  when  you  arise  stand  close  to  an  open 
window  or  door  and  inhale  as  deeply  as  you  can, 
then  exhale  promptly.  Do  this  at  least  ten  times. 
Do  the  same  thing  in  the  evening  before  you  retire, 
when  all  your  tight  clothing  has  been  removed. 
Another  excellent  habit  to  form  is  to  breathe  deeply 
as  you  walk  along  to  school.  Inhale  while  you  take 
eight  or  ten  steps.  Then  exhale  either  quickly  or 
slowly.  Repeat  this  ten  or  twelve  times  and  you 
will  feel  the  invigorating  effects. 

It  is  quite  as  important  to  have  plenty  of  pure  air 
during  the  night  as  during  the  day.  This  can  be 
secured  by  keeping  the  windows  in  the  sleeping  room 
open  all  night,  all  the  year  around.  Many  people 
are  building  outside  sleeping  porches  in  order  to 
sleep  in  pure  air. 

Diseases  of  the  breathing  organs.  The  diseases 
that  commonly  affect  the  breathing  organs  are  colds, 
grippe,  tuberculosis,  and  pneumonia.  All  of  these 
are  caused  by  disease  germs  or  bacteria.  Persons 
who  have  these  diseases  may  scatter  the  germs  by 


404  STUDIES' IN  SCIENCE 

ordinary  breathing,  but  especially  by  coughing,  sneez- 
ing and  spitting.  The  germs  fly  around  in  the  air 
and  are  inhaled  by  well  persons.  If  a  person  is  in 
excellent  health,  the  white  blood  corpuscles  may  at 
once  kill  off  the  germs  and  he  will  feel  no  ill  effects. 
On  the  other  hand,  the  bacteria  may  get  a  foothold, 
begin  to  grow  and  multiply  and  bring  on  disease,  at 
once  or  in  a  short  time. 

If  all  people  who  have  these  diseases  were  very 
careful  not  to  scatter  the  germs,  there  would  soon 
be  none  of  them  to  spread.  When  you  have  a  cold 
you  should  keep  away  from  other  people  as  much  as 
possible.  When  you  cough  or  sneeze  you  should 
hold  a  handkerchief  over  your  mouth  and  nose.  In 
no  case  should  you  spit  upon  the  sidewalk  or  about 
the  house.  Tuberculosis  is  probably  spread  more  by 
the  habit  of  spitting  than  in  any  other  way. 

Clean  air  means  clean  homes,  clean  streets,  clean 
alleys,  clean  clothing,  and  clean  bodies.  Since  air  is 
constantly  moving,  bits  of  dust  with  germs  are  con- 
stantly being  carried  around  for  people  to  inhale. 
Out-of-doors  the  air  changes  so  constantly  that  there 
is  little  danger.  But  indoors  the  air  may  become 
so  laden  with  germs  that  every  breath  carries  some 
into  the  body. 

To  keep  dust  out  of  the  home  and  school,  then, 
is  one  of  the  ways  to  aid  in  preventing  disease.  Rugs 


AIR  405 

on  the  floors  that  may  be  taken  out-of-doors  fre- 
quently and  cleaned,  vacuum  cleaners  that  prevent 
dust  from  being  scattered,  oiled  cloths  for  dusting, 
all  help  to  keep  the  air  pure. 

Moisture  in  the  air.  Another  thing  that  we  should 
give  attention  to  is  the  amount  of  water  vapor  in  the 
air,  as  the  heated  air  of  our  homes  is  usually  too  dry 
for  health.  More  moisture  should  be  supplied.  With 
steam  or  hot-water  systems,  vessels  of  water  should 
be  placed  on  or  under  the  radiator  so  that  moisture 
may  constantly  evaporate  from  them.  What  provi- 
sion does  a  hot  air  furnace  make  for  a  constant  sup- 
ply of  moisture  in  the  air?  Look  at  the  side  of  the 
furnace  for  a  small  water  pan.  This  opens  into  the 
jacket.  Water  in  this  pan  evaporates  and  the  vapor 
is  carried  with  the  warm  air  into  the  rooms. 


CHAPTER  XXIV 

WEATHER 

Materials.  A  thermometer,  an  almanac,  daily 
weather  maps,  pages  in  your  notebook  to  keep  weather 
and  sun  records.  Weather  maps  may  be  obtained 
by  teachers  for  use  in  schools  from  the  Weather 
Bureau  at  Washington  or  from  the  nearest  weather 
station  in  the  state. 

Study.  If  you  try  to  decide  what  the  term  weather 
means  you  will  find  that  it  includes  many  things 
that  you  have  studied  in  the  last  three  chapters. 
It  means  certain  conditions  of  the  atmosphere 
with  reference  to  temperature,  moisture  and  wind. 
Have  you  ever  thought  how  closely  the  weather 
touches  the  lives  of  all  people?  Farmers,  gardeners, 
and  fruit  growers  are  largely  dependent  upon  the 
weather  for  success  or  failure  in  raising  their  crops. 
Weather  conditions  more  than  anything  else  caused 
primitive  man  to  erect  shelters  from  which  have 
finally  evolved  our  well-arranged,  comfortable  homes. 
Clothing,  too,  to  a  large  extent,  originated  because 
man  needed  protection  from  the  weather.  Even  now 
the  weather  has  much  to  do  with  the  kind  of  clothing 

406 


WEATHER 


407 


that  is  used  during  the  different  seasons.  In  fact,  it 
will  not  be  hard  for  you  to  make  a  long  list  of  indus- 
tries and  customs  that  exist  because  of  weather. 

Man  cannot  control  the  weather,  but  by  informing 
himself  about  the  laws  that  govern  winds  and  storms, 
and  by  keeping  in  touch  with  the  information  sent 
out  by  the  Weather  Bureau,  he  can  usually  plan  his 
activities  in  a  way  to  prevent  the  weather  from 
injuring  his  crops  or  other  work. 

A  good  way  to  find  out  facts  about  the  weather 
is  to  keep  a  weather  record  for  a  period  of  days  or 
weeks.  Place  in  your  notebook  or  on  a  large  piece 
of  paper  the  following  outline  arid  keep  the  record 
for  a  month  or  longer.  If  you  have  no  barometer 
leave  out  the  column  for  pressure. 

WEATHER  RECORD 


Tem- 

Wind 

Wind 

• 

Precipita- 

Date 

Hour 

per- 

Direc- 

Veloc- 

Pressure 

Sky 

tion  or 

Remarks 

ature 

tion 

ity 

rainfall 

Dec. 

9  a.  m. 

warm 

t 

Light 

29.5  in. 

cumulus 

Foggy 

60* 

clouds 

this  a.  m. 

Note  to  teacher:  Weather  observations  and  records  should  be- 
gin in  the  fall  not  later  than  November  and  be  continued  at  least 
a  week  at  a  time  until  you  are  ready  to  take  up  the  regular  study 
after  the  chapters  on  heat,  water  and  air.  The  record  may  be  kept 
without  interfering  with  the  other  studies. 


408  STUDIES  IN  SCIENCE 

These  observations  may  be  taken  without  instru- 
ments. However,  if  the  school  has  a  thermometer 
the  temperature  should  be  reported  in  degrees.  If 
there  is  no  thermometer  then  the  terms  warm,  hot, 
very  hot,  chilly,  cold,  or  very  cold  may  be  used. 

The  direction  of  the  wind  may  be  indicated  by  an 
arrow.  An  arrow  pointing  toward  the  top  of  the 
page  indicates  that  the  wind  is  traveling  north.  Is  a 
wind  named  from  the  direction  it  is  going  or  the 
direction  from  which  it  is  coming!  Velocity  means 
the  distance  the  wind  travels  per  hour.  The  follow- 
ing words  may  be  used  to  indicate  velocity.  These 
terms  are  suggested  by  the  U.  S.  Weather  Bureau. 
Calm,  when  there  is  no  perceptible  wind;  light,  when 
there  is  just  enough  wind  to  move  the  branches  of 
the  trees ;  brisk,  when  only  branches  sway ;  high,  when 
whole  trees  sway. 

Under  sky,  report  whether  it  is  clear,  partly  cloudy, 
or  overcast,  and  the  kind  of  clouds.  Precipitation 
means  falling  weather  of  any  sort — rain,  snow,  hail, 
etc.  Under  remarks,  report  any  item  of  interest  that 
does  not  appear  under  the  other  headings.  Thus, 
for  December  3,  a  heavy  frost  last  night,  or  for 
December  16,  a  slight  snow  fell  this  afternoon. 

At  the  end  of  the  month  make  a  short  summary 
derived  from  your  observations.  How  many  fair 
days!  How  many  cloudy?  How  many  in  which 


WEATHER 


409 


there  was  precipitation?  What  was  the  general 
direction  of  the  wind  when  the  temperature  was 
warmest?  When  the  temperature  was  coldest?  From 
what  direction  did  the  rain  come?  From  what  direc- 
tion did  the  snow  come?  What  was  the  direction 
of  the  wind  during  the  cloudy  weather,  etc.? 

Temperature.  Your  record  will  show  some  inter- 
esting facts  concerning  temperature,  especially  if 
your  observation  extends  over  a  period  of  several 
months.  Usually  the  temperature  is  lower  in  the 
morning  than  in  the  evening.  It  is  highest  early  in 
the  afternoon.  One  day  may  be  very  cold;  the  next 
from  thirty  to  forty  degrees  warmer.  Sudden  changes 
in  temperature  are  dependent  upon  wind  direction 
and  velocity,  but  the  more  constant  changes  through- 
out the  day  and  from  month  to  month  are  due  to  the 
relative  positions  of  the  earth  and  sun. 

Arrange  the  following  outline  in  your  notebook. 
Make  observations  twice  each  week  for  a  period  of 
two  or  three  months.  The  best  time  to  begin  is  in  the 
latter  part  of  November  or  early  in  December. 

SUN  OBSERVATIONS 


Date 

Sunrise 

Altitude  of 
Sun  at  Noon 

Sunset 

Time 

Position 

Time 

Position 

> 

410  STUDIES  IN  SCIENCE 

To  get  the  time  of  sunrise  and  sunset  consult  an 
almanac.  This  is  more  accurate  than  getting  it  by 
observation.  Use  great  care  in  getting  the  position 
of  the  sun.  In  the  first  place  try  to  find  a  spot  from 
which  you  can  see  the  sky  down  to  the  horizon.  In 
the  morning  at  sunrise  or  soon  afterward  stand  fac- 
ing due  east.  Is  the  sun  north  or  south  of  that  point! 
Now  turn  facing  due  south.  How  many  degrees  are 
there  on  the  horizon  between  due  east  and  due  south! 

Every  circle  no  matter  how  large  or  how  small  has 
exactly  360  degrees  in  it.  Since  from  the  point  due 
east  to  due  south  is  one-fourth  the  distance  around 
the  circle  of  the  horizon,  it  is,  of  course,  90  degrees 
between  these  two  points. 

Now  face  the  sun  and  decide  whether  or  not  it  is 
half  way  between  east  and  south.  If  not,  how  many 
degrees  south  of  east  is  it!  Estimate  as  accurately 
as  you  can  the  number  of  degrees.  Fix  the  position 
in  relation  to  some  object  as  a  tree,  telephone  post, 
or  building.  Note  carefully  by  means  of  this  object 
whether  or  not  the  sun  remains  in  the  same  position 
week  after  week.  If  it  does  not,  determine  which 
way  it  is  moving. 

Make  the  same  kind  of  observations  to  determine 
the  varying  positions  of  the  sun  at  sunset. 

At  noon  stand  out-of-doors  where  you  can  see  the 
sun  and  sky.  The  point  directly  over  your  head  is 


WEATHER  411 

called  the  zenith.  Now  face  the  south.  Trace  with 
your  eye  the  curved  line  of  the  sky  from  your  zenith 
to  the  point  in  the  southern  horizon  directly  in  front 
of  you.  How  many  degrees  is  it  I 

Now  determine  the  position  of  the  sun  on  this  line. 
How  far  above  the  horizon  does  it  seem  to  be?  Is  it 
half  way  to  the  zenith?  Fix  its  position  with  refer- 
ence to  some  object  and  determine  from  week  to  week 
whether  it  is  getting  lower  or  higher.  The  distance 
the  sun  is  above  the  horizon  is  called  its  altitude. 

You  can  make  a  simple  instrument  with  which  to 
measure  the  exact  altitude  of  the  sun  at  noon.  This 
instrument  is  called  a  clinometer.  To  make  a  clinom- 
eter use  a  square  of  cardboard  or  pasteboard.  On 
this  draw  a  quarter  of  a  circle  to  represent  the  line 
from  the  zenith  to  the  horizon.  Mark  this  off  into 
degrees  from  zero  to  ninety.  Mark  off  the  ninety  into 
eighteen  equal  parts.  Each  part  is  five  degrees.  Now 
divide  these  into  one-degree  spaces.  Tack  the  paste- 
board onto  a  board  and  drive  a  nail  a  short  distance 
into  it  at  the  square  corner.  Fasten  the  board  a  few 
feet  from  the  ground  on  the  east  or  west  side  of  the 
house  at  the  south  end,  so  that  the  sun  will  shine  upon 
it  at  noon.  The  shadow  cast  by  the  nail  will  fall  upon 
the  scale  indicating  the  altitude  of  the  sun.  In  mak- 
ing the  clinometer  you  should  know  on  which  side  of 
the  house  it  is  to  be  placed.  If  it  is  on  the  east  side. 


412 


STUDIES  IN  SCIENCE 


put  the  zero  at  the  upper  right-hand  corner  of  the 
scale;  if  on  the  west,  begin  the  scale  at  the  upper  left- 
hand  corner. 

Discussion.  'Your  observations  show  that  before 
December  22  the  sun  is  moving  farther  southward 
both  morning  and  evening.  It  also  shows  that  its 
altitude  is  lower.  After  this  date  it  moves  north- 
ward and  at  noon  its  altitude  is  higher. 


Fig.  75.  The  amount  of  heat  received  depends  upon  the  angle  at 
which  the  sun's  rays  strike  the  surface  of  the  earth.  The  same  num- 
ber of  rays  fall  on  a  smaller  area  at  A  than  at  B. 

It  is  this  movement  of  the  sun  that  brings  the  sea- 
sonal weather  changes.  When  the  sun  is  far  to  the 
south  its  rays  strike  the  earth  with  a  greater  slant 
than  when  it  is  farther  north  and  higher  at  noon. 
This  means  that  slant  rays  do  not  have  as  much  power 
to  heat  the  earth  as  those  that  are  more  nearly 
vertical. 

A  study  of  Fig.  75  will  explain  the  reason  for  this. 


WEATHER  413 

The  two  sets  of  parallel  lines  represent  the  same  num- 
ber of  heat  rays  from  the  sun  striking  the  earth.  With 
your  ruler  measure  the  difference  in  space  covered  by 
each  set.  Since  A  covers  a  much  less  space  it  can,  of 
course,  heat  the  portion  that  it  strikes  much  more  than 
if  it  were  spread  out  to  cover  a  space  as  large  as  B. 
Hence  the  slanting  rays  of  winter  cannot  heat  the 
earth  as  much  as  the  more  vertical  rays  of  summer  are 
able  to  do.  The  same  is  true  during  each  day.  The 
slanting  rays  of  morning  and  evening  do  not  have  the 
same  power  to  heat  as  the  more  vertical  rays  of  noon. 

Nooh 


g.   76.     Diagram,  showing  the  difference  in  the  angles  at  which 
the  sun's  rays  strike  the  earth  at  sunrise,  noon,  and  sunset. 

You  already  know  that  the  rays  of  heat  from  the 
sun  called  radiant  heat  are  absorbed  by  the  earth. 
The  air  near  the  earth  is  warmed,  not  directly  from 
the  sun  but  from  the  earth,  partly  because  it  touches 
the  warm  earth  and  partly  because  heat  from  the 
earth  radiates  into  the  air.  When  the  heat  rays  of 
the  sun  strike  certain  objects  on  the  earth  the  heat 
instead  of  being  absorbed  is  reflected  back  into  the 
air.  From  this  vou  can  easilv  see  that  the  air  near 


414  STUDIES  IN  SCIENCE 

the  earth  is  much  warmer  than  the  air  higher  up. 
Some  tests  have  been  made  that  show  the  temperature 
from  12  to  15  degrees  colder  at  a  height  of  one  mile 
above  the  earth  and  from  70  to  80  degrees  colder 
five  miles  from  the  ground. 

Clouds.  If  you  have  never  formed  the  habit  of 
observing  the  clouds  you  will  find  their  study  won- 
derfully interesting.  The  sky,  like  the  sea,  has  endless 
variations  which  are  due  mostly  to  cloud  forma- 
tions. As  you  already  know,  clouds  are  masses  of 
condensed  water  vapor  floating  in  the  air.  Some- 
times these  masses  are  very  low,  not  more  than  one- 
fourth  of  a  mile  above  the  earth.  Sometimes  they 
are  six  or  seven  miles  high.  They  vary  in  appear- 
ance with  their  height,  size,  density  and  amount  of 
rain  in  them.  The  names  given  to  the  most  common 
cloud  forms  are  cirrus,  cumulus,  stratus,  and  nimbus. 
Cirrus  are  light,  feathery  clouds  that  are  high  in  the 
sky.  Sometimes  they  are  mere  white  streaks  across 
the  blue.  These  clouds  rarely  indicate  an  approach- 
ing storm.  However,  when  they  look  like  plumes 
with  torn  and  frayed  edges  and  are  moving  rapidly 
and  gathering  into  larger  masses,  rain  or  snow  is 
usually  indicated. 

Cumulus  is  the  great  mass  of  clouds  so  familiar  in 
the  summer  time.  Like  great  mountains  with  rounded 
tops,  sometimes  they  are  glistening  white  all  over, 


WEATHER 


415 


Fig.  77.  Forms  of  clouds:  I.  Cirro-cumulus,  often  called  a  mack- 
erel sky.  II.  Stratus,  seen  most  frequently  near  the  horizon  before 
or  after  sunset.  Cumulus  clouds  sometimes  form  in  straight  lines 
and  are  called  cumulo-stratus.  III.  Cirrus;  high,  fringy  clouds  that 
seldom  predict  a  storm.  IV.  Cumulus;  when  large  often  changing 
to  nimbus,  producing  a  sudden  storm. 


416  STUDIES  IN  SCIENCE 

sometimes  white  on  one  side  and  dark  on  the  other. 
Often  they  float  around  during  the  morning,  then 
break  up  and  disappear.  When  they  do  this  they 
are  called  dry  weather  clouds.  Sometimes  they  col- 
lect together  growing  larger  and  darker.  When  this 
is  the  case  they  usually  bring  a  thunder  shower.  When 
they  reach  this  stage  they  are  called  cumulo-nimbus. 

Stratus  are  the  clouds  that  appear  as  layers  across 
the  sky.  Light  ones  are  often  visible  at  sunset  and 
sunrise.  They  are  also  seen  at  other  times  during 
the  day.  Any  cloud  that 'has  no  special  form  but 
spreads  out  like  a  sheet  or  in  layers  is  a  stratus  cloud. 

Nimbus  is  a  cloud  from  which  precipitation  is  occur- 
ring; hence  any  of  the-  other  forms  change  to  nimbus 
as  soon  as  they  begin  to  fall  in  the  form  of  rain  or 
snow. 

Sometimes  you  will  see  rather  high  in  the  sky  a 
wavy  mass  of  white  clouds  which  look  like  white 
curly  wool.  This  is  a  combination  of  cirrus  and 
cumulus  known  as  cirro-cumulus.  It  is  also  spoken 
of  as  a  mackerel  sky.  You  will  find  other  apparent 
combinations  as  strato-cumulus  and  cirro-stratus; 
high,  white,  leathery  clouds  in  layers. 

By  watching  the  clouds  every  opportunity  you  have 
you  will  soon  learn  to  recognize  the  different  forms 
and  be  able  to  tell  somewhat  accurately  what  clouds 
are  likely  to  bring  rainfall. 


WEATHER  417 

Winds.  Your  study  of  convection  currents  tells 
you  how  wind  is  produced.  It  is  nothing  but  a  move- 
ment of  air  due  to  unequal  pressure.  The  unequal 
pressure  is  caused  chiefly  by  a  difference  in  tempera- 
ture. Heat  makes  the  air  expand  and  become  light, 
The  heavy  air  rushes  toward  the  light  area  and  the 
result  is  wind.  All  the  winds  on  the  earth's  surface 
are  caused  in  this  way.  You  can  see  why  there  are 
constant  winds  blowing  toward  the  heat  equator  from 
the  north  on  one  side  and  from  the  south  on  the  other. 
The  movement  of  the  earth  on  its  axis  changes  the 
course  of  these  constant  winds  so  that  north  of  the 
equator  they  blow  from  the  northeast  instead  of  from 
due  north,  and  south  of  the  equator  they  blow  from 
the  southeast.  These  are  known  as  trade  winds. 

Just  as  in  a  room  the  warm  air  from  a  radiator 
or  stove  is  pushed  upward,  moves  outward  at  the 
ceiling,  becomes  cooler  and  drops  downward  in  parts 
of  the  room  most  remote  from  the  stove,  so  on  the 
earth  at  the  equator  the  heated  air  moves  upward, 
and  when  it  reaches  a  certain  height  it  spreads  out, 
cools,  and  drops  down  to  the  earth  again.  We  live 
in  the  part  of  America  north  of  the  region  where  the 
air  drops  downward.  It  spreads  out  toward  both  the 
north  and  south.  We  are  in  the  northern  belt.  The 
deflection  due  to  the  turning  of  the  earth  upon  its  axis 
causes  the  air  to  move  eastward,  so  we  have  what 


418  STUDIES  IN  SCIENCE 

are  known  as  the  westerly  winds.  They  do  not  blow 
steadily  eastward  as  you  know.  They  are  influenced 
by  mountains  and  valleys  and  by  local  differences  in 
temperature  and  pressure.  We  have  constantly  mov- 
ing across  the  United  States  from  west  to  east  what 
are  called  "lows"  and  "highs."  A  low  is  an  area 
of  low  air  pressure,  a  high  of  heavy  air,  or  high 
pressure. 

In  a  low  the  air  is  moving  from  all  sides  toward 
the  center.  In  a  high  it  is  moving  from  the  center 
outward  on  all  sides.  The  kind  of  weather  we  have 
depends  largely  upon  whether  a  low  or  a  high  is 
passing  over  or  near  us.  This  movement  is  shown 
on  a  weather  map. 

Weather  map.  Study  a  weather  map.  Make  a  list 
of  everything  you  find  on  it.  Study  the  explanation 
given  in  fine  print  in  the  lower  corner.  This  will 
enable  you  to  interpret  all  the  terms  and  symbols 
used.  Trace  a  low  as  it  moves  eastward  for  several 
days  and  decide  whether  it  brings  fair  or  stormy 
weather.  Trace  several  isotherms  into  a  low  to  see 
in  which  part  of  the  low  the  highest  temperature  is 
found.  The  isotherms  are  the  dotted  lines  and  con- 
nect places  having  equal  temperature.  In  the  same 
way  trace  the  isobars.  These  are  the  solid  lines. 
They  connect  places  having  equal  pressure. 


WEATHER 


419 


Weather  maps  are  made  under  the  direction  of  the 
Weather  Bureau  at  Washington,  D.  C.  The  first 
weather  observations  for  the  public  were  begun  in 


|r 

1 

. '••    l'-;,ill!! 


420  STUDIES  IN  SCIENCE 

1871.  The  Weather  Bureau  became  a  definite  part 
of  the  Department  of  Agriculture  in  1891.  The  daily 
map  gives  definite  facts  concerning  temperature,  pres- 
sure, wind  direction,  velocity  and  rainfall  all  over 
the  United  States.  When  you  learn  to  read  one  of 
these  maps  you  can  tell  what  kind  of  weather  people 
are  having  in  any  part  of  the  country.  More  than 
that,  you  can  tell  by  the  position  of  the  lows  and  the 
direction  they  are  moving  what  kind  of  weather  you 
are  likely  to  have  during  the  next  twenty-four  hours. 
The  weather  forecast  found  on  the  map  and  printed 
in  newspapers  is  made  from  a  study  of  the  weather 
jnap  by  men  who  are  employed  by  the  Weather 
Bureau. 

Information  for  the  making  of  maps  is  obtained 
from  weather  stations  which  are  found  in  all  parts 
of  the  country.  At  these  stations  observations  are 
taken  at  8  A.  M.  and  again  at  8  P.  M.  every  day. 
These  are  telegraphed  to  the  Weather  Bureau  and 
experts  prepare  the  maps  and  send  them  out.  Each 
state  has  a  weather  bureau  center  which  prepares 
maps  for  its  own  region. 

The  value  of  warnings  sent  out  by  the  Weather 
Bureau  to  agriculturists  and  seamen  is  beyond  esti- 
mation. It  is  fair  to  state  that  property  worth  at 
least  $30,000,000  is  saved  annually  in  the  United 
States  by  the  work  of  the  Weather  Bureau. 


SPRING  STUDIES 

CHAPTER  XXV 

POULTRY  AND  POULTRY  PROJECTS 

Material.  Poultry  of  the  neighborhood,  feathers 
and  eggs. 

Study.  Make  a  list  of  all  the  different  kinds  of 
poultry  in  your  community.  Which  kind  is  raised  in 
greatest  numbers!  Do  many  people  keep  just  one 
breed?  How  many  keep  several  breeds'?  If  you  have 
poultry  at  home,  find  out  the  number  of  each  kind, 
and  estimate  their  present  market  valueti  Among 
your  hens  how  many  are  more  than  one  year  old? 
How  many  pullets?  How  many  cocks?  How  many 
eggs  do  you  get  daily?  Try  to  discover  by  observa- 
tion which  are  laying  more,  the  pullets  or  the  older 
hens. 

Study  of  a  chicken.  Chickens,  and  all  other  poul- 
try, are  birds,  and  as  members  of  that  great  group 
of  animals  they  have  certain  characteristics. 

Organs  of  locomotion.  Note  the  feet.  Are  they 
placed  near  the  front  or  the  back  part  of  the  body? 
How  many  toes  are  there?  Compare  with  one 
another  as  to  length.  How  many  are  actually  used  in 
walking?  What  is  found  at  the  end  of  each  toe?  Do 

421 


422  STUDIES  IN  SCIENCE 

hens  wajk  on  their  toes  or  on  the  soles  of  their  feet? 
What  protective  covering  has  the  foot!  Why  are 
scales  a  better  covering  for  the  feet  and  toes  than 
feathers  ?  Look  for  chickens  that  have  feathers  on 
their  feet.  Try  to  find  out  how  the  toes  hold  the 
chicken  on  the  perch.  What  other  use  is  made  of 
the  feet  than  walking? 

Watch  a  hen  fly  and  note  the  movement 
of  the  wings.  Spread  out  a  wing  and  study  the  ar- 
rangement of  the  feathers.  When  the  wing  moves 
downward  does  the  air  pass  between  the  large  feath- 
ers? In  what  direction  does  the  chicken  move  with 
the  downward  stroke  of  the  wing? 

At  your  first  opportunity  look  at  the  bones  of  a 
chicken's  wing  and  compare  with  those  of  your  arm. 

Watch  the  flight  of  wild  birds.  What  use  is  made 
of  the  tail? 

Procuring  food.  Watch  a  hen  feeding.  What  is 
the  chief  organ  that  she  uses?  Describe  the  beak  or 
bill  and  state  what  characteristics  it  has  that  fit  it 
for  its  purpose.  Is  it  hard  or  soft;  sharp  or  blunt? 
To  what  extent  does  it  differ  in  different  breeds  of 
chickens?  Name  the  different  kinds  of  food  you 
have  seen  hens  eating,  and  the  different  ways  of 
using  the  beak.  Is  the  food  chewed  or  swallowed  at 
once? 

Sense  organs.     Name  all  the  sense  organs  you  can 


POULTRY  AND  POULTRY  PROJECTS 


423 


find  on  the  head  of  a  chicken.  Note  the  position, 
shape  and  color  of  the  eyes.  Can  the  hen  see  the 
same  object  with  both  eyes  at  the  same  time?  Look 
for  eyelids.  If  you  have  a  tame  hen  that  you  can 
hold  in  your  arm,  touch  the  head  near  the  eye  and 
note  what  happens.  Find  the  ears.  Describe  them. 
What  evidence  have  you  that  hens 
and  other  birds  hear  well?  Notice 
the  position  of  the  nostrils,  the 
small  openings  on  the  upper  part 
of  the  bill. 

Feathers.  Make  a  collection  of 
all  the  different  kinds  of  feathers 
that  are  found  on  one  chicken. 
You  should  have  one  or  more  from 
the  tail,  the  back,  breast,  neck, 
legs,  and  one  from  each  of  the  dif- 
ferent parts  of  the  wing.  These 
will  include  the  stiff  outer  wing 
feathers,  the  primaries ;  the  row 
of  large  feathers  next  to  these,  the 
secondaries;  and  the  finer,  over- 
laping  feathers,  the  coverts. 

Examine  one  of  the  tail  feathers.  How  many 
distinct  parts  do  you  find?  What  are  the  names  of 
the  parts?  (See  Fig.  79.)  Pull  the  barbs  of  the  web 
apart  to  determine  how  they  are  fastened  together. 


A 

Fig.  79.  Parts  of 
a  feather.  A,  Quill; 
B,  Fluff;  C,  The  web 
composed  of  barbs. 


424  STUDIES  IN  SCIENCE 

Compare  the  different  feathers  as  to  the  amount  of 
web  and  fluff.  Which  have  more  fluff,  the  feathers  of 
the  back  or  breast?  Which  of  all  the  feathers  have 
the  least  fluff?  Which  the  greatest  amount?  What 
part  of  each  feather  is  exposed  to  the  weather?  Look 
closely  to  see  how  much  of  each  web  is  exposed.  What 
is  the  value  of  this  great  overlapping?  What  is  the 
use  of  the  undercoat  of  fluff?  Place  the  tips  of  your 
fingers  close  to  the  body  in  the  fluffy  part  of  the 
feathers.  Now  place  them  on  the  outer  part  of  the 
web.  Explain  the  difference  in  temperature.  Eecall 
what  you  learned  about  conductors  and  non-conduc- 
tors of  heat  and  decide  in  which  class  feathers 
belong. 

How  does  the  hen  succeed  in  keeping  her  feathers 
smooth  and  in  a  condition  to  shed  water?  Watch  one 
oiling  and  preening  her  feathers.  Where  is  the  oil 
gland  situated? 

Make  a  chart  showing  the  different  kinds  of 
feathers. 

Other  types  of  poultry.  If  you  have  an  opportun- 
ity make  a  comparative  study  of  geese,  ducks  and 
turkeys.  Note  the  special  adaptations  of  the  bills, 
feet  and  feathers  of  ducks  and  geese  for  life  in  or 
near  water. 

Discussion.  Some  of  the  questions  that  have  aris- 
en with  your  study  cannot  be  answered  by  observa- 


POULTRY  AND  POULTRY  PROJECTS  425 

tion.  The  characteristics  that  you  have  discovered 
are  in  the  main  common  to  all  birds  and  that  gives 
them  an  added  interest. 

Perhaps  you  are  not  certain  that  the  chicken 
walks  on  its  toes.  The  segment  that  we  often  call 
the  lower  part  of  the  leg  is  really  the  foot.  The 
"  drumstick "  corresponds  to  your  leg  below  the  knee, 
and  the  second  joint  to  your  thigh.  When  a  bird  is  on 
the  roost  the  toes  curve  round  the  perch  and  the 
weight  of  the  body  bends  the  joints  and  tightens  the 
sinews  so  that  the  bird  sleeps  without  danger  of  fall- 
ing. In  fact,  a  perching  bird  has  to  rise  up,  straight- 
ening its  legs  somewhat,  before  it  can  release  its  toes 
from  the  perch. 

The  flight  of  birds  is  based  upon  a  principle  of 
physics.  The  large  primary  feathers,  when  the  wing 
is  spread,  overlap  to  such  a  degree  that  no  air  passes 
between  them.  The  bird  strikes  downward  with  the 
wing  and  the  force  exerted  sends  it  forward  and  up- 
ward just  as  a  boat  is  sent  forward  when  you  strike 
the  water  with  the  oar.  The  curved  wing  enables  the 
bird  to  press  harder  upon  the  air  than  if  it  were 
straight.  You  noticed  that  the  barbs  on  the  front 
edge  of  a  large  wing  feather  lie  close  and  almost  par- 
allel to  the  quill.  This  prevents  them  from  being 
torn  apart  by  the  wind.  With  the  up  stroke  the  wing 
is  turned  slightly  sidewise  and  offers  less  resistance 


426  STUDIES  IN  SCIENCE 

to  the  air.  So  while  the  down  stroke  pushes  the 
bird  upward  and  forward,  the  up  stroke  does  not 
push  the  bird  downward.  The  tail  is  spread  in 
flight  and  serves  as  a  rudder  to  guide  the  bird. 

The  bill  of  a  chicken  is  well  adapted  to  procuring 
food.  It  is  sharp  and  strong  and  is  used  to  break  up 
hard  particles  as  well  as  to  pick  up  the  food.  As 
chickens  have  no  teeth  the  food  is  swallowed  whole. 
First  it  passes  into  the  crop  where  it  is  moistened, 
then  into  the  stomach  where  it  is  further  moistened 
with  digestive  fluids,  and  then  into  the  gizzard  where 
it  is  ground  up  by  small  pebbles  and  other  hard 
substances.  The  bill  is  also  used  as  a  weapon  of  de- 
'fense,  to  preen  and  oil  the  feathers,  and  to  turn  the 
eggs  during  incubation. 

The  eyes  of  a  chicken  are  closed  by  the  lower  lid 
instead  of  the  upper.  There  is  a  thin  semi-transpar- 
ent membrane,  sometimes  called  the  third  eyelid, 
present  in  the  eyes  of  all  birds.  It  spreads  over  the 
eye  like  a  veil  and  is  a  protection  against  strong 
light  and  other  injuries. 

The  ears  are  small  irregular  openings  on  the  sides 
of  the  head.  Usually  they  are  pretty  well  covered 
with  feathers.  Although  the  external  ear  is  so  in- 
conspicuous, birds  possess  a  very  keen  sense  of  hear- 
ing. 

Breeds  of  chickens.    If  there  are  representatives  of 


POULTRY  AND  POULTRY  PROJECTS  427 

different  breeds  of  chickens  in  your  neighborhood, 
visit  them,  study  their  characteristics,  and  prepare 
to  report  in  class.  Collect  from  poultry  journals  and 
farm  papers  pictures  of  different  breeds  and  make  a 
chart  or  booklet. 
Poultry  raisers  group  the  breeds  into  four  great 


Fig.  80.     The  dual-purpose-type. 

classes :  egg  breeds,  meat  breeds,  dual-purpose,  and 
fancy  breeds. 

Egg  breeds  were  originally  European  birds  and 
are  known  as  the  Mediterranean  class.  They  are 
small  active  chickens.  The  hens  are  noted  for  the 
great  number  of  eggs  they  lay  and  for  the  fact  that 
they  rarely  want  to  "sit."  The  most  common  va- 


428  STUDIES  IN  SCIENCE 

rieties  are  Leghorns,  Minorca,  Black  Spanish  and  Blue 
Andalusian. 

The  meat  breeds  are  known  as  the  Asiatic  class,  be- 
cause the  original  stock  probably  came  from  Asia. 
There  are  three  common  varieties,  the  Brahmas, 
Cochins  and  Langshans.  They  are  very  large, 
heavy  chickens  and  produce  a  large  amount  of  meat. 
They  are  not  good  layers  and  are  of  little  value  in 
raising  chicks. 

The  general  purpose  breeds  are  more  popular  in 
most  places  than  the  others.  They  belong  to  the  Amer- 
ican class,  because  they  have  been  produced  by  Ameri- 
can breeders.  They  are  medium  in  size  and  are  com- 
paratively good  layers,  hence  they  are  useful  in  pro- 
ducing both  meat  and  eggs.  They  are  also  better 
adapted  than  other  breeds  to  raise  and  care  for  the 
young  chicks.  The  common  varieties  are  the  Ply- 
mouth Eocks,  Wyandottes,  Rhode  Island  Reds, 
Orpingtons,  and  Dominiques. 

Compare  the  different  breeds  with  each  other  as  to 
size,  color,  shape,  and  value.  The  fifth  breed  named 
above  is  of  little  practical  value.  Occasionally  some 
one  raises  bantams  or  other  fancy  breeds  for  the 
novelty  of  it. 

Care  of  poultry.  In  caring  for  your  poultry  you 
must  consider:  1.  Housing,  2.  Feeding,  3.  Arrange- 
ments for  producing  chicks. 


POULTRY  AND  POULTRY  PROJECTS 


429 


Housing.  What  different  kinds  of  poultry  houses 
are  there  in  your  community?  What  points  would 
you  consider  in  making  a  poultry  house? 

Size  and  shape  of  the  house.  The  size  and  shape 
are  of  some  importance.  The  building  should  not  be 
too  wide.  Sixteen  feet  is  wide  enough.  Many  are 
but  twelve  feet.  The  house  should  be  large  enough 
so  that  each  bird  may  have  a  floor  space  of  from 
five  to  six  feet.  A  house  twelve  by  twenty-four  feet 


Fig.  81.    A  good  poultry  house. 

is  about  the  right  size  for  fifty  hens,  or  perhaps  six- 
teen by  sixteen  gives  better  floor  space  for  arranging 
nests  and  roosts. 

Connected  with  the  poultry  house  there  should 
be  a  run  where  the  chickens  may  get  out  into  the 
open  air  except  in  the  most  severe  weather. 

Light  and  air.  It  is  very  essential  to  have  plenty 
of  sunlight  in  the  house.  The  way  to  manage  this 


430  STUDIES  IN  SCIENCE 

is  to  have  the  building  face  the  south  with  a  number 
of  windows.  A  house  sixteen  feet  long  should  have 
two  windows  each  containing  eight  square  feet.  Good 
ventilation  is  as  important  as  plenty  of  sunlight.  A 
way  must  be  provided  for  exchange  of  air.  Some 
poultry  houses  are  so  open  that  while  there  is  plenty 
of  fresh  air,  there  are  too  many  drafts.  Many  plans 
have  been  tried  for  securing  ventilation  without 
drafts.  Probably  the  best  method  yet  found  is  the 
cloth  window  pane.  This  may  be  made  of  muslin  or 
cheese  cloth  and  may  be  placed  in  one  of  the  south 
windows  instead  of  glass.  It  may  be  so  arranged  that 
during  severe  weather  the  glass  window  may  partly 
close  the  opening. 

Dryness.  Too  much  moisture  is  detrimental  to  the 
health  of  poultry.  This  means  that  the  building 
should  be  placed  on  well  drained  ground.  Some 
poultrymen  elevate  the  floor  several  inches  with  a 
layer  of  gravel.  On  top  of  this  is  a  cement  floor.  Ce- 
ment makes  an  excellent  floor.  It  is  easy  to  clean 
and  at  the  same  time  keeps  out  rats. 

Roosts.  Eoosts  should  be  comfortable,  and 
arranged  so  that  cleaning  may  be  easily  done.  There 
are  many  different  devices.  Perhaps  the  most  satis- 
factory is  to  make  the  roosts  out  of  two  by  two 
lumber  with  the  upper  edges  rounded.  Place  them 
about  two  and  one-half  to  three  and  one-half  feet 


POULTRY  AND  POULTRY  PROJECTS  431 

from  the  floor.  Under  them  place  a  platform  to  catch 
the  droppings. 

Nests.  Proper  placing  of  the  nests  is  a  problem 
of  importance.  Perhaps  the  most  practical  method  is 
to  place  the  nests  under  the  platform  described 
above.  In  this  way  the  same  floor  space  is  used 
for  nests  and  roosts.  Many  poultry  raisers  prefer 
to  have  platform,  nests,  and  roosts  movable,  so  that 
they  may  be  taken  out,  cleansed  and  disinfected. 

Describe  the  nests  you  have  seen.  What  size  were 
they?  Were  they  placed  in  a  strong  light  or  in  a 
dim  light?  There  are  a  number  of  different  kinds 
of  nests.  A  nest  should  be  from  twelve  to  fourteen 
inches  square  and  from  six  io  eight  inches  deep.  It 
should  be  shaded  in  some  way  from  the  strong  light. 
Hens  seem  to  prefer  a  rather  dark  place  for  their 
nests. 

Feeding.  Make  a  list  of  the  different  kinds  of 
poultry  foods  used  in  your  district.  .What  grains 
are  fed?  Are  they  used  dry  or  moist?  Whole  or 
ground?  Chickens,  like  all  other  animals,  need  a 
certain  amount  of  starchy  foods,  or  carbohydrates, 
proteids,  and  fats.  Laying  hens  require  a  large 
amount  of  proteid  food  because  the  white  of  egg  is 
almost  pure  proteid.  Every  poultryman  decides  for 
himself  the  exact  amount  of  the  different  feeds  to 
give.  Grain  of  some  kind,  part  whole  and  part 


432  STUDIES  IN  SCIENCE 

ground,  is  used  by  all.  The  whole  grains  should  be 
scattered  in  a  layer  of  straw  on  the  ground  or  floor 
so  that  the  chickens  will  be  compelled  to  exercise  in 
order  to  get  them.  Meat  scraps  and  sour  milk 
supply  the  proteid.  Green  food  of  some  sort  is  quite 
essential.  This  may  be  supplied  by  vegetables,  such 
as  cabbage, 'beets,  turnips,  etc.,  and  by  grass,  clover, 
alfalfa  and  sprouted  oats.  Fine  gravel  or  crushed 
oyster  shells  should  always  be  supplied,  as  these  aid 
the  digestive  process.  Chickens  require  plenty  of 
clean  water  as  well  as  food.  The  drinking  pan  should 
be  emptied  and  fresh  water  put  in  every  day. 

Chicks.  How  early  in  the  spring  do  poultry  rais- 
ers set  hens?  Start  incubator!  If  possible,  visit  a 
a  home  where  an  incubator  is  used.  Describe  it. 
How  is  the  heat  supplied?  Can  you  trace  the  convec- 
tion current  from  its  source  to  the  eggs?  How  warm 
must  the  incubator  be  kept?  The  heat  is  usually 
supplied  by  ,a  small  oil  lamp  or  gas  heater.  When 
the  chicks  are  taken  from  the  incubator  how  are  they 
kept  warm?  Different  methods  are  employed,  but 
usually  they  are  placed  in  a  brooder,  which  is  a 
small  box  with  strips  of  cloth  among  which  the 
chicks  may  cuddle  down  to  keep  wTarm.  There  are 
many  different  kinds  of  brooders,  some  of  which  are 
furnished  with  artificial  heat. 

The  feeding  of  young  chicks  is  of  great  importance. 


POULTRY  AND  POULTRY  PROJECTS         433 

For  forty-eight  hours  after  hatching  the  chick  does 
not  require  any  food.  The  yolk  of  the  egg  furnishes 
it  food  during  this  period.  The  first  food  may  be 
hard  boiled  eggs  chopped  fine,  shell  and  all,  mixed 
with  stale  bread,  cracked  wheat  or  corn;  or  the  first 
meal  may  be  stale  bread  crumbs  moistened  in  milk. 
After  a  few  days  the  chick  may  be  fed  a  mixture  of 
bran,  corn-meal,  shorts,  and  scraps  of  meat.  Most 
people  prefer  to  use  the  food  dry.  Some  poultrymen 
cook  all  the  food  for  the  first  few  weeks.  With  dry 
food  plenty  of  milk  should  be  used.  Sour  milk  is 
quite  as  good  or  better  than  sweet. 

Value   of   poultry.    Name   all   the   different   prod- 
ucts produced  by  poul- 
try.     How    important 
are     these     products  ? 
What   is   the   average 
price  of  eggs?     Of 
spring  chickens   or 
broilers  per  pound? 
Of  one-year  old  hens? 
What  is  the  price  of 
feathers?     Poultry 
products  are  becoming         Fig>  82    A  good  type  of  hen 
more  and  more  important  each  year.    The  demand  for 
choice  chickens  and  fresh  eggs  is  constantly  increasing 
and   the   prices    are   high    enough    to   make   poultry 


434  STUDIES  IN  SCIENCE 

raising  a  successful  business.  When  is  the  price  of 
eggs  highest?  How  may  eggs  be  packed  to  ship  by 
parcel  post? 

Poultry  projects.  You  should  begin  to  think  about 
raising  poultry  on  your  own  account  if  you  live  in  the 
country  or  in  a  town  where  you  may  have  space 
enough  for  a  small  house  and  run.  Choose  a  breed 
that  you  think  will  give  best  returns.  You  can  start 
with  one  hen  and  a  setting  of  eggs,  or  you  can  buy 
a  number  of  young  chicks  that  are  a  day  or  two  old. 
If  your  parents  raise  poultry  you  may  get  enough 
from  them  for  your  start.  Many  poultrymen  sell 
and  ship  large  numbers  of  young  chicks.  Keep  a 
very  careful  record  of  your  project. 

Record. 

1.  Expenditures. 

a.  Number  and  market  value  of  chickens  you  start  with. 

b.  Cost  of  necessary  equipment. 

c.  Cost  of  feed. 

d.  Approximate  cost  of  labor. 

2.  Receipts. 

a.  Number  of  eggs. 

b.  Value  at  market  price. 

c.  Number  of  chicks  raised. 

d.  Value  of  those  sold. 

e.  Value  of  those  kept  for  breeding  purposes. 

f.  Value  of  those  used  at  home. 

3.  Net  profits. 

4.  Notes  that  will  be  of  value  for  future  reference. 

If  you  live  in  a  place  where  ducks  or  geese  are 


POULTRY  AND  POULTRY  PROJECTS  435 

raised,  you  may  be  interested  in  starting  a  project 
with  these  instead  of  with  chickens. 

A  poultry  club  in  the  school  will  add  to  the  value 
of  the  projects.  If  this  is  undertaken,  plans  should 
be  made  for  an  exhibit  with  a  display  of  eggs  and 
chickens  or  other  poultry.  If  practicable  a  poultry 
house  may  be  equipped  on  the  school  grounds  and 
poultry  raised  on  a  cooperative  plan.  Some  of  the 
children  may  take  the  responsibility  of  caring  for 
the  stock  during  vacation. 


CHAPTER  XXVI 

BIRDS 

Material.  Birds  of  the  community,  charts,  pic- 
tures, books  and  notebooks;  when  possible  a  pair  of 
field  or  opera  glasses. 

Study.  You  should  become  acquainted  with  every 
bird  in  the  vicinity  of  your  home  and  school. 
There  is  but  one  way  to  accomplish  this  and  that  is 
to  study  birds  at  first  hand,  out-of-doors.  Getting 
acquainted  means  not  only  learning  to  identify  birds, 
but  finding  out  everything  you  can  about  their  lives 
and  habits. 

If  you  are  not  familiar  with  many  birds,  you 
cannot  begin  your  observation  at  a  better  time  than 
late  winter  or  very  early  spring.  At  this  time  the 
number  of  different  birds  is  not  great  and  you  can 
easily  learn  to  know  them  all  before  the  spring  mi- 
gration brings  in  a  large  number  of  new  species. 

In  order  to  make  an  intelligent  study,  you  should 
know  the  names  of  the  different  parts  of  a  bird.  Study 
Fig.  83  until  you  are  able  to  name  all  the  parts  when 
you  look  at  a  live  bird.  When  you  go  out  on  a  field 
trip,  form  the  habit  of  taking  a  small  notebook  with 

436 


BIRDS  437 

you.  Eeserve  two  pages  for  each  bird.  The  fol- 
lowing outline  will  be  found  helpful  in  keeping  a 
record : 

1.  Date: 

2.  Weather  conditions: 

3.  Name: 

4.  Where  is  the  bird: 

5.  Size:  compare  with  wren,  English  sparrow,  robin,  crow. 

6.  Colors: 

Head Crown Nape Bill 

Back rump wings tail 

Throat breast belly sides feet 

7.  Movements  and  habits.     Note  special  characteristics  of  flight, 
movements  upon  the  ground,  feeding  habits  and  food,  nesting  habits, 
time  of  nesting,  material  used,  location  of  nest,  share  of  the  work 
done  by  the  male,  by  the  female,  care  of  the  young. 

Do  not  think  that  you  must  make  a  complete 
record  with  your  first  observation,  but  add  to  it  from 
time  to  time  as  you  become  better  acquainted  with 
the  bird.  One  of  the  interesting  things  about  bird 
study  is  that  no  matter  how  long  you  may  have 
known  a  bird,  you  are  constantly  finding  out  new 
facts  about  it. 

Suggestions  for  field  study.  1.  Move  slowly  and 
quietly.  2.  If  you  have  companions  avoid  talking  to 
them,  or  speak  in  a  very  low  tone.  3.  Study  one 
bird  till  you  are  sure  of  its  colors;  do  not  try  to  study 
two  or  three  at  the  same  time.  4.  Listen  attentively 
to  the  notes  and  songs  so  that  in  time  you  will  be 
able  to  identify  birds  by  sound,  as  well  as  by  sight. 


438 


STUDIES  IN  SCIENCE 


5.  Learn  to  imitate  as  many  of  the  notes  as  you  can, 

6.  As  far  as  possible  keep  the  sun  at  your  back  in 
order  to  see  the  colors  more  distinctly.     7.  Plan  to 
make  some  studies  in  the  early  morning.     An  hour 
before  breakfast  will  often  give  better  results  than 
two  or  three  hours  in  the  middle  of  the  day.  Next  to 
the  early  morning  hours  the  late  afternoon  is  the  best 
time  to  see  birds. 


'Crown 


Fig.  83.     Parts  of  a  bird. 

Bird  Groups.  Birds  may  be  grouped  into  four 
classes  with  reference  to  the  period  of  time  and  the 
season  during  which  they  remain  in  your  locality. 

1.  Permanent   residents   are   the    species   that   are 
found  in  the  same  region  the  year  around. 

2.  Winter  residents  spend  the  winter  in  one  local- 


BIRDS  439 

ity   and   go   farther   north    to   nest   and   rear   their 
young. 

3.  Summer   residents   nest   in   one   region   but   go 
farther  south  to  spend  the  winter. 

4.  Migratory  visitors   are   birds   that  nest  in   the 
far  North,  winter  in  the  South,  and  stop  at  places 
between  for  a  few  days  or  weeks  during  their  spring 
and  fall  journeys.     You  may  discover  for  yourself  the 
many  birds  that  belong  to   each   of  these   different 
groups. 

Birds  may  also  be  grouped  with  reference  to  their 
structure  and  appearance.  Orinthologists  have  used 
structural  characteristics  to  classify  birds  into 
orders,  families,  genera  and  species. 

If  you  look  in  any  good  bird  book  you  find  besides 
the  common  name,  a  scientific  name.  This  is  made  up 
of  two  words  designating  the  genus  and  the  species. 
If,  for  example,  you  look  at  the  description  of  a 
flicker,  you  find  in  italics  after  the  common  name 
colaptes  auratus,  which  is  the  scientific  name.  Then 
if  you  look  farther  you  find  that  the  flicker  and  all 
other  woodpeckers  are  placed  in  a  group  by  them- 
selves because  they  all  have  similar  characteristics. 
These  constitiute  the  woodpecker  family.  A  number 
of  families  that  have  similar  characteristics  are  put 
together  into  a  larger  group  called  an  order. 

It  is  worth  while  finding  out  some  of  the  family 


440 


STUDIES  IN  SCIENCE 


characteristics  of  the  birds  with  which  you  become 
acquainted.  The  parts  of  a  bird  that  are  commonly 
considered  in  placing  birds  into  family  groups  are 
the  bill  and  feet.  The  nesting  and  feeding  habits  and 
the  musical  powers  are  in  many  cases  also  consid- 
ered. 
Descriptions.  Select  a  number  of  good  bird  pic- 


Fig.  84.     Adaptations  in  the  bills  of  birds. 

tures.    Compare  the  bills  and  feet  to  determine  how 
they  differ.     Put  together  those  that  have  similar  bills 
and  you  will  probably  have  some  representative  fam- 
ily group. 
Families.     Describe   the   bills    of   song   sparrows, 


BIRDS 


441 


the  vesper  sparrow,  the  goldfinch,  the  cardinal,  the 
rose-breasted  grosbeak. 

You  find  in  every  case  a  stout,  rather  short,  con- 
ical bill.  These  birds  belong  to  the  sparrow  or 
finch  family.  The  hard  stout  bills  are  adapted  for 


Fig.  85.    Adaptations  in  .the  feet  of  birds. 

-     '         •.••!.»>».'.  l:i.~ 

the  crushing  of  seeds.  These  are  the  great  seed 
eaters  among  the  birds.  Many  of  them  are  also 
noted  for  destroying  insects,  especially  hard-shelled 
insects.  The  rose-breasted  grosbeak  is  one  of  the  few 
birds  that  is  especially  fond  of  the  potato  beetle. 


442  STUDIES  IN  SCIENCE 

The  bills  of  the  members  of  the  swallow  family  are 
short  and  sharp  and  very  wide  at  the  base.  These 
birds  spend  most  of  their  time  on  the  wing  catching 
insects  in  the  air.  Their  wide  mouths  are  admirably 
adapted  to  this  kind  of  life.  They  have  very  long 
wings  and  rather  small,  weak  feet.  When  they  alight 
they  choose  a  telephone  wire  or  a  small  twig  which 
their  small  toes  can  grasp  with  ease. 

If  you  look  closely  at  pictures  of  wood  warblers  you 
find  the  bills  long,  slender,  and  pointed;  just  the  kind 
to  snap  up  insects  from  the  leaves  or  bark  of  trees 
and  shrubs.  The  warblers  are  all  small  birds  and 
most  of  them  are  brightly  colored. 

The  mockingbird  family  has  long,  rather  slender, 
slightly  curved  bills.  Their  bodies  are  slender  and 
their  tails  long.  They  are  noted  for  their  wonder- 
ful musical  power.  Besides  the  true  mockingbird,  the 
brown  thrasher  and  catbird  are  the  most  common 
members  of  this  family. 

Wrens  are  closely  related  to  the  mockingbirds,  but 
are  placed  in  a  family  by  themselves.  Their  bills  are 
similar  to  those  of  the  mockingbirds.  They,  too,  are 
great  musicians. 

The  creeper  family  is  represented  by  but  one  species 
here  in  America,  That  is  the  small  brown  bird  that 
you  see  creeping  up  the  trunks  of  trees.  The  bill  is 
very  slender,  curved,  and  sharp  pointed;  With  this 


BIRDS  443 

needlelike  bill  the  bird  is  able  to  get  insect  eggs  and 
tiny  larvae  from  the  smallest  cracks  and  crevices  of 
the  bark. 

The  thrush  family  includes  two  of  our  most  familiar 
birds,  the  robin  and  bluebird.  The  bills  are  long, 
rather  slender,  and  pointed.  They  are  adapted  for 
eating  either  insects  or  fruit.  All  the  thrushes  except 
the  two  common  birds  named  have  spotted  breasts. 
You  may  have  observed  that  the  young  of  both 
robins  and  bluebirds  have  the  characteristic  spotted 
thrush  breast.  The  thrushes  rank  high  among  bird 
musicians. 

If  you  have  examined  the  bills  of  the  kingbird,  pee 
wee,  or  phoebe,  you  note  that  they  are  slightly  curved 
at  the  tip  and  wide  at  the  base.  These  birds  belong 
to  the  fly  catcher  family.  This  family  is  noted  for 
catching  insects  on  the  wing.  The  bird  usually  sits  on 
a  dead  branch  of  a  tree  watching  for  insects.  As  one 
flies  by  the  bird  darts  out  and  skillfully  catches  it, 
usually  returning  to  the  same  perch  again  and  again. 

The  blackbird  family  comprises  a  large  number 
of  birds  that  differ  considerably  in  their  habits  and 
structure.  Their  bills  are  rather  long,  deep,  and 
pointed,  adapted  to  picking  up  a  variety  of  foods, 
insects,  seeds,  and  fruits.  Some  of  them  have  very 
little  musical  ability,  while  others  are  good  songsters. 
Besides  all  the  different  kinds  of  blackbirds,  the 


444  STUDIES  IN  SCIENCE 

meadow  larks,  orioles,  and  bobolinks  belong  to  this 
family. 

All  the  families  we  have  described  thus  far  belong 
to  one  great  order  called  pass'eres  or  perching  birds. 
The  arrangement  of  the  toes  is  the  same  in  all  of 
these  birds;  that  is,  three  toes  point  forward  and  one 
backward. 

The  members  of  the  woodpecker  family  have  strong, 
slightly  blunt,  chisel-like  bills  which  enable  the  birds 
to  peck  holes  in  trees.  The  foot  has  two  toes  that 
point  forward  and  two  that  point  backward.  This 
arrangement,  with  the  sharp  claws,  adapts  the  foot  to 
tree  climbing.  The  tail  also  aids  in  climbing.  You 
notice  that  it  is  short  and  that  the  feathers  are  pointed 
and  stiff.  They  help  to  prop  the  bird  against  the  tree 
while  it  is  creeping  upward.  The  tongue  of  the  wood- 
pecker is  quite  remarkable.  It  is  very  long  and  ends 
in  a  hard  tip  with  sharp  barbs  along  the  side.  This 
enables  the  bird  to  draw  from  their  hiding  places 
the  borers  that  feed  under  the  bark  of  trees. 

Hawks,  eagles,  and  owls  belong  to  an  order  known 
as  raptores  or  birds  of  prey.  All  of  these  birds  have 
strong  hooked  bills  adapted  for  tearing  flesh,  very 
strong  feet  and  claws  used  for  catching  and  carrying 
prey,  and  long  strong  wings  that  enable  them  to  fly 
great  distances. 

Shore  birds.    If  you  live  near  water,  lakes,  ponds, 


BIRDS  445 

or  rivers  you  will  have  an  opportunity  to  become  ac- 
quainted with  shore  birds  and  swimmers. 

The  shore  birds  are  represented  by  the  snipes,  sand- 
pipers and  stilts.  They  have  very  long  slender  bills 
which  enable  them  to  probe  around  in  mud  and  sand 
in  search  of  insects  and  other  choice  morsels  to  eat. 
The  legs  are  long  and  are  bare  above  the  heel  joint. 
This  makes  it  possible  for  them  to  wade  in  shallow 
water  without  getting  the  feathers  wet.  The  neck 
also  is  long. 

Ducks  and  geese  are  common  representatives  of  the 
family  of  swimmers.  The  bill  is  flat  and  broad  with 
a  sieve  along  the  edges  of  the  mandibles.  When  the 
birds  get  their  mouths  full  of  water,  thin  mud, 
and  particles  of  food,  the  sieve  allows  the  water  and 
mud  to  flow  out  and  leaves  the  food.  The  toes  of 
these  birds  are  webbed  so  that  they  may  be  used  as 
paddles  in  swimming.  The  body  is  boat  shaped,  a 
characteristic  which  also  aids  in  swimming.  Besides 
ducks  and  geese,  swans  belong  to  this  family. 

Value  of  birds.  Make  a  list  of  all  the  ways  in  which 
birds  are  of  value  to  us.  It  is  no  easy  matter  to  esti- 
mate accurately  the  good  that  birds  do  in  the  world. 
They  destroy  countless  numbers  of  insect  pests. 
It  is  probably  fair  to  say  that  without  the 
aid  of  birds  many  of  our  farm  crops  would  be  part- 
ially if  not  wholly  destroyed  every  season.  It  is  not 


446  STUDIES  IN  SCIENCE 

farm  crops  alone  that  birds  protect,  but  also  gardens, 
orchards,  and  forests. 

You  have  only  to  watch  a  pair  of  wrens,  thrashers, 
robins  or  grosbeaks  during  the  nesting  season,  work- 
ing incessantly  from  dawn  to  dark  collecting  insects 
from  the  yard  and  garden,  to  appreciate  what  great 
benefactors  they  are.  The  seed-eating  birds,  the 
finches  and  sparrows,  aid  us  in  devouring  quantities 
of  weed  seeds  every  year.  The  birds  of  prey,  hawks, 
and  owls,  are  of  great  importance  because  of  the 
number  of  small  rodents,  mice,  rats,  gophers,  ground 
squirrels  and  the  like,  that  they  destroy. 

Aside  from  their  economic  value  birds  are  of  impor- 
tance because  of  their  influence  upon  our  lives.  No 
other  phase  of  nature  can  bring  more  genuine  pleasure 
than  bird  study.  To  know  birds,  to  appreciate  their 
beauty  of  song  and  color,  to  love  them  for  themselves 
and  for  their  interesting  ways  and  habits,  will  bring 
you  joy  not  only  now,  but  all  the  days  of  your  life. 

Enemies  of  birds.  Make  a  list  of  the  enemies  of 
birds. 

1.  Destruction  of  nesting  places.  The  clearing  of 
woodlands  is  progressing  to  such  an  extent  that  in 
many  localities  the  birds  are  disappearing  because 
they  no  longer  have  places  in  which  to  build  their 
nests  and  rear  their  young.  The  breaking  up  of 
prairie  lands  and  the  draining  of  swamps  in  the 


BIRDS  447 

Middle  West  have  already  driven  large  numbers  of 
birds  from  that  region. 

2.  Destruction  of  drinking  and  bathing  places  by 
the  draining  of  ponds,  open  ditches  and  small  streams. 

3.  Cats.    Professor  Forbush,  of  Massachusetts,  esti- 
mates that  a  single  cat  is  responsible  for  the  death  of 
about  fifty  song  birds  a  year. 

4.  The  robbing  of  nests  by  boys  who  have  a  mania 
for  collecting  eggs. 

5.  The  destruction  of  birds  for  millinery  purposes. 

6.  English    sparrows.      These   foreign   birds    drive 
away  from  our  homes  many  of  our  most  beneficial  and 
beautiful  song  birds. 

7.  Red  squirrels.    These  are  becoming  so  numerous 
in  some  towns   that  they   are  destroying   scores   of 
bird  nests  every  season. 

Protection  and  care.  You  can  do  much,  not  only  to 
protect  birds  from  their  enemies,  but  to  actually  in- 
crease the  numbers  in  your  community.  One  of  the 
first  things  is  to  provide  nesting  places.  Every  coun- 
try community  should  have  a  bird  refuge  in  connec- 
tion with  each  farm.  A  few  shrubs  or  low  trees  along 
the  highway  or  in  clumps  in  fence  corners  will  keep 
in  the  neighborhood  scores  of  useful  birds  that  will 
pay  for  their  nesting  site  by  destroying  myriads  of 
noxious  insects. 

Boxes  or  bird  houses  may  be  provided  for  birds  that 


448  STUDIES  IN  SCIENCE 

nest  in  cavities.  Use  old  weather  beaten  lumber,  or, 
if  new  material  is  used,  paint  the  houses  a  dull  gray  or 
brown.  For  wrens  and  chickadees  make  the  hole  for 
the  entrance  about  one  inch  in  diameter.  This  will 
prevent  English  sparrows  from  entering.  Larger  birds 
that  nest  in  boxes  are  the  bluebird,  tree  swallow, 
purple  martin,  nuthatch,  flicker,  titmouse,  phoebe,  and 
screech  owl. 

Tin  cans,  old  tea  and  coffee  pots,  and  gourds  may 
be  used  instead  of  boxes.  You  can  attract  some  birds 
by  furnishing  building  material  for  them.  Place 
twine  or  yarn  on  bushes  for  orioles,  a  pan  of  mud  for 
robins,  and  hairs,  dry  grass,  rootlets  and  threads  for 
other  birds.  Birds  need  water  both  for  drinking  and 
bathing.  Pretty  bird  basins  or  baths  may  be  pur- 
chased, but  you  can  easily  arrange  your  own  at  small 
cost. 

A  little  basin  of  cement  with  sloping  bottom  and 
fringed  with  rocks  and  ferns  may  be  placed  in  a 
hollow  in  the  back  yard.  Common  granite  iron  pans 
from  two  to  four  inches  deep  may  be  used.  Place 
a  layer  of  clean  sand  or  fine  gravel  in  the  bottom  or  a 
flat  stone  for  small  birds  to  stand  upon.  If  the  pan  is 
set  upon  a  block  or  stump  a  few  feet  from  the  ground, 
cats  are  not  so  likely  to  disturb  the  birds  while  in  the 
bath. 

Help  get  rid  of. all  the  stray  cats  in  the  neighbor- 


BIRDS 


449 


Lood.  If  you  have  cats  of  your  own,  feed  them  with 
la  meat  diet  so  they  will  not  attack  the  birds  because 
of  hunger.  Do  all  you  can  to  train  them  to  leave 
birds  alone,  or  keep  them  indoors  during  the  nesting 
[season. 

Birds  may  be  kept  near  your  home  all  winter  by 
[supplying  food  for  them.  Nuthatches,  chickadees, 
hairy  and  downy  woodpeckers,  brown  creepers  as  well 
as  jays,  will  feed  upon  beef  suet  tied  firmly  in  the 
crotch  of  a  tree  or  suspended  from  a  branch.  Meat 
rinds  or  shank  bones  may  also  be  used.  Native 
sparrows,  juncoes,  gold  finches  and  other  seed  eating 
birds  may  be  attracted  by  a  feeding  tray  made  out  of 
boards  and  fastened  to  some  support  four  or  five  feet 
high.  This  tray  should  be  kept  supplied  with  chaff 
from  the  haymow,  sunflower  seeds,  millet,  and  other 
seeds.  During  the  early  spring  days  when  insect  food 
is  scarce,  robins  and  bluebirds  enjoy  crumbs  from  the 
table. 

Consult  the  Shrub  List,  page  460,  to  find  what 
shrubs  have  berries  that  attract  birds  both  in  summer 
and  winter.  Besides  the  shrubs,  the  following  trees 
furnish  attractive  food  for  birds:  white  and  red  mul- 
berry, mountain  ash,  hawthornes,  June  berry,  wild 
cherry  and  flowering  dogwood. 

Do  not  wear  birds  on  your  hat,  even  if  the  millin- 
er insists  that  they  are  made  of  chicken  feathers.  The 


450  STUDIES  IN  SCIENCE 

principle  remains  the  same  whether  they  are  real  or 
artificial. 

With  the  help  of  your  teacher,  look  up  the  laws  of 
your  own  state  for  the  protection  of  birds  and  do  all 
you  can  to  see  that  they  are  enforced. 

\ 

BIRD  LISTS 

1.  Birds  that  feed  upon  insects  injurious  to  field  crops:     Meadow 
lark,  bobwhite,   dickcissel,   indigo  bunting,  killdeer,  Maryland  yel- 
low throat,    redwing  blackbird,   bobolink,   brown   thrasher,   bronze 
grackle,  cowbird,  horned  lark,  song  sparrow,  field  sparrow,  other 
native  sparrows,  plover. 

2.  Birds  that  feed  upon  insects  injurious  to  garden  and  fruit 
crops:      House  wren,   catbird,  rose-breasted   grosbeak,   robin,   blue- 
bird,   oriole,    chickadee,    downy    and    hairy    woodpecker,    chipping 
sparrow,  yellow  warbler,  nuthatch,  brown  creeper,  mocking-bird. 

3.  Birds  that  destroy  flying  insects  about  the  home:      Chimney 
swift,  barn  swallow,  tree  swallow,  purple  martin,  kingbird,  night 
hawk,  phoebe. 

4.  Birds  that  are  especially  beneficial  to  forest  and  shade  trees: 
All  the  warblers,  scarlet  tanager,  summer  tanager,  the  cuckoo,  vireo, 
thrush,  pewee,  titmouse,  whip-poor-will,  chuck-wilFs-widow,  chewink, 
white-eyed  vireo,  all  woodpeckers,  nuthatch. 

?.  Birds  that  feed  upon  weed  seeds:  Goldfinch,  white-throated 
sparrow,  white-crowned  sparrow,  tree  sparrow,  junco,  mourning 
dove. 

6.  Birds  that  destroy  mice,  ground  squirrels  and  injurious 
rodents:  Red-tailed  hawk,  red -shouldered  hawk,  marsh  hawk,  rough- 
legged  hawk,  screech  owl,  short-eared  owl,  barred  owl,  snowy  owl, 
barn  owl,  horned  owl. 


CHAPTER    XXVII 

LANDSCAPE  GAEDENING 

If  you  look  at  any  well  arranged  home  or  school 
grounds  you  find  five  distinct  kinds  of  plants  used 
to  make  them  attractive.  First  there  is  grass  in  the 
lawn  or  open  stretches,  then  there  are  trees,  shrubs, 
vines  and  flowering  plants.  The  artistic  arrange- 
ment of  these  different  groups  of  plants  in  relation 
to  each  other  and  to  buildings,  walls,  and  walks  or 
drives  constitutes  what  we  call  landscape  gardening. 
The  men  and  women  who  make  a  business  of  plan- 
ning and  planting  such  grounds  are  known  as  land 
scape  gardeners  or  landscape  architects. 

While  you  can  not  attempt  to  do  the  work  of  the 
landscape  gardener,  you  can  learn  some  of  the  under- 
lying principles,  and,  in  cooperation  with  your 
parents  and  teachers,  undertake  a  few  projects  to 
make  your  home  and  school  grounds  more  beautiful. 
This  need  not  interfere  with  your  vegetable  projects. 
You  may  very  well  undertake  the  care  of  a  vegetable 
plot  and  a  home  improvement  plan  at  the  same  time. 

451 


452  STUDIES  IN  SCIENCE 

THE  LAWK 

In  any  plan  for  improvement  of  grounds  the  lawn 
should  receive  first  consideration.  It  is  the  canvas  of 
the  landscape  picture  "upon  which  the  artist  paints 
with  tree  and  bush  and  flower  as  the  painter  does 
upon  his  canvas  with  brush  and  pigment.'' 

In  all  the  states  north  of  latitude  38  to  40°,  Ken- 
tucky blue-grass  is  the  favorite  lawn  grass.  For  spe- 
cial conditions,  such  as  very  shady  spots,  dry  sunny 
slopes,  or  for  low  wet  lands,  other  grasses  are 
mixed  with  this.  In  fact,  other  seeds  are  frequently 
mixed  with  blue-grass  in  starting  an  ordinary  lawn. 
Some  people  use  other  grasses  and  some  use  white 
clover.  Barron  in  his  book  entitled  "Lawns"  sug- 
gests the  following  mixture  for  any  lawn  that  has 
a  clay  soil: 

Kentucky   blue-grass    50% 

English  rye  20% 

Fancy  red  top    


The  rye  grows  rapidly  and  covers  the  surface  with 
green  in  a  short  time.  After  a  few  years  if  the  blue- 
grass  does  well*  it  takes  complete  possession  of  the 
space.  In  the  South,  Bermuda  is  the  chief  lawn 
grass. 

Other  mixtures  suggested  by  the  same  writer  are: 


LANDSCAPE  GARDENING  453 

For  terraces  or  slopes 

Creeping  bent  or  Rhode  Island  bent 40% 

Crested  dog's  tail 25% 

Canada   blue-grass    25% 

Kentucky  blue-grass 10% 

For  shaded  places 

Kentucky  blue-grass 40% 

Wood  meadow  grass 40% 

Various  leaved  fescue   10% 

Crested  dog's  tail   ; 10% 

Some  localities  are  so  shady  that  it  is  impossible 
to  get  a  stand  of  grass.  In  that  case  other  plants 
may  be  used  to  cover  the  ground  and  give  a  pleas- 
ing effect.  Myrtle  is  excellent  for  this  purpose.  So 
is  common  ground  ivy. 

Blue-grass.  Material.  A  grass  plot  in  home  or 
school  yard;  a  small  piece  of  sod  taken  from  some 
corner  where  it  will  not  be  missed;  specimens,  of  seed 
heads;  seeds. 

The  suggested  topics  for  blue-grass  may  be  used 
for  any  other  lawn  grass. 

Problem.  What  are  the  characteristics  that  make 
blue-grass  a  good  lawn  grass?  Note  the  habit  of 
growth  of  the  grass.  Try  to  separate  the  individual 
plants  from  each  other.  How  close  together  are  they? 
Try  to  pull  up  one  grass  plant.  What  happens  ? 
Why  does  it  break  off  instead  of  coming  up  by  the 
roots?  What  direction  do  the  leaves  take  in  their 


454  STUDIES  IN  SCIENCE 

growth!  How  are  they  fastened  to  the  stem?  Eemove 
a  leaf  and  examine  it.  Compare  the  lengths  of  sheath 
and  blade.  Determine  whether  the  blade  is  flat  or 
folded  toward  the  mid-rib.  Examine  a  number  before 
you  decide. 

Rootstock  and  roots.  Examine  the  piece  of  sod. 
How  many  distinct  structures  do  you  find  penetrating 
the  ground!  Describe  each.  Wash  all  the  soil  out 
of  a  small  piece  in  order  to  see  the  parts  clearly. 
What  is  the  greatest  number  of  rootstocks  that  you 
find  growing  from  a  single  plant!  What  is  the  direc- 
tion of  growth!  What  is  there  at  the  free  end!  Of 
what  advantage  to  the  plant  is  the  rootstock! 

Seeds.  Study  the  seed-head.  How  tall  is  it!  How 
does  it  branch!  Where  are  the  seeds!  Eemove  all 
the  seeds  from  one  head  and  measure.  Describe  the 
seeds  as  to  size  and  color.  Compare  with  those  of 
other  grasses.  Make  a  collection  of  all  the  different 
heads  of  grass  seeds  available  and  mount  them  on  a 
stiff  cardboard. 

Experiment.  Effect  of  depth  of  planting  on  germ- 
ination and  growth.  In  a  box  of  soil  plant  several 
rows  of  seeds  at  depths  varying  from  a  mere  cover- 
ing to  two  inches.  Determine  which  germinate  and 
grow  best.  If  possible  make  the  experiment  out-of- 
doors  also.  What  is  the  price  of  blue-grass  seed! 
How  large  a  space  will  a  pound  sow!  How  many 


LANDSCAPE  GARDENING  455 

pounds  in  one  bushel?  How  much  will  it  cost  to  sow 
an  acre? 

The  home  lawn.  Examine  your  home  lawn. ' 
Which  way  does  it  slope?  Has  it  any  terraces?  Is 
it  in  good  condition?  If  not,  what  can  you  do  to  im- 
prove it?  Look  for  dead  leaves  and  other  trash,  bare 
spots,  weed  patches,  uneven  spots.  What  rules  are 
followed  regarding  mowing? 

Discussion.  From  your  observation  you  find  that 
blue-grass  grows  in  a  very  crowded  condition.  This 
is  one  of  the  characteristics  that  makes  it  an  excel- 
lent lawn  grass. 

The  underground  parts  are  quite  as  important. 
You  found  the  great  mass  of  fine  fibrous  roots  that 
help  to  make  a  firm  turf  or  sod  and  the  thicker  root- 
stock  which  is  an  underground  stem.  If  you  exam- 
ined it  closely  you  found  that  it  has  nodes  with  scale 
leaves,  and  a  growing  bud  at  the  end.  The  rootstock 
grows  horizontally  and  enables  the  grass  to  spread 
evenly  over  the  ground.  It  is  a  great  advantage  to 
the  plants  during  severely  cold  or  dry  weather.  All 
the  parts  above  ground  may  be  killed,  but  the  root- 
stock  with  its  buds  remains  uninjured  and  sends  up 
new  plants  as  soon  as  the  proper  conditions  of 
moisture  and  warmth  are  restored. 

Blue-grass  sends  up  its  flowering  head  in  the  early 
summer,  and  the  seeds  ripen  within  a  few  weeks. 


456  STUDIES  IN  SCIENCE 

This  kind  of  a  head  with  many  branches  is  called  a 
panicle. 

*  Starting  a  lawn.  If  you  wish  to  start  a  new  lawn, 
the  first  requirement  is  a  deep  seed-bed  of  rich 
mellow  soil.  Level  the  surface,  leaving  a  slight  slope 
from  the  house  to  the  road  or  street  if  desired.  You 
may  start  a  lawn  in  two  ways,  by  the  use  of  sods  or 
by  seeds.  The  latter  is  less  expensive  and  is  the 
one  commonly  used.  The  seed  may  be  sown  in  the 
fall  any  time  before  the  ground  freezes,  or  in  the 
spring.  Spring  seeding  should  be  done  as  early  as 
possible  so  that  the  plants  will  get  a  fair  start  before 
dry,  hot  weather. 

Choose  a  day  to  sow  when  the  wind  is  not  blowing 
briskly,  scatter  the  seeds  evenly  and  thickly,  about 
one  pound  to  100  square  yards.  Rake  the  soil  lightly. 
If  possible  run  a  roller  over  it.  If  it  does  well  it  will 
be  ready  to  mow  in  six  weeks  or  two  months. 

Caring  for  the  lawn.  If  you  find  bare  spots  in 
your  lawn  rake  out  all  the  trash,  put  in  some  fresh 
soil,  then  seed  thickly.  If  there  are  weeds  dig  them 
out  and  sow  grass  seeds  in  their  place.  If  the  lawn  is 
uneven  the  use  of  a  heavy  roller  will  greatly  improve 
it.  Eolling  at  least  once  in  the  spring  is  good  for 
any  lawn  whether  uneven  or  not. 

The  lawn  should  be  mowed  often  enough  to  keep  a 
smooth  velvety  grass  covering.  In  dry  weather  care 


LANDSCAPE  GARDENING  457 

should  be  taken  not  to  mow  too  close  to  the  ground 
as  there  is  danger  of  injuring  the  roots.  In  fact,  it 
is  best  to  have  the  mower  set  high  at  all  times. 
Evening  is  a  better  time  for  mowing  than  morning. 
Do  you  see  why?  The  grass  has  the  cool  night  in 
which  to  recover  from  the  shock  of  the  cutting.  In 
dry  weather  it  is  best  to  allow  the  clippings  to  lie 
instead  of  catching  them  or  raking  them  up. 

If  you  water  your  lawn  you  will  find  that  a 
thorough  drenching  once  or  twice  a  week  will  keep 
it  in  better  condition  than  a  light  sprinkle  every 
day. 

Home  projects.  No  home  project  that  you  can 
undertake  will  give  you  more  real  pleasure  and  satis- 
faction than  caring  for  the  lawn.  You  will  have 
some  enemies  to  contend  with.  The  most  common 
and  the  hardest  to  combat  are  weeds.  Eemoving 
them  root  and  all  is  the  surest  way  to  get  rid  of  them. 
Do  not  allow  a  single  one  to  go  to  seed.  (See  Weeds, 
p.  77.) 

1.     SHKUBS 

Material.  Shrubs  of  the  neighborhood,  park, 
nurseries,  and  woodlands,  catalog  containing  price 
lists. 

Study.  Make  a  list  of  all  the  shrubs  in  your  district 
whose  names  you  know.  Choose  several  for  special 


458  STUDIES  IN  SCIENCE 

study.  What  is  their  habit  of  growth?  How  do  they 
differ  from  trees?  What  is  the  height  and  color 
of  the  stem?  Are  the  twigs  stiff  and  erect  or  droop- 
ing? Examine  the  twigs  for  buds  and  scars.  Which 
shrubs  have  retained  their  fruit  or  berries  over 
winter?  Have  you  seen  any  birds  feeding  upon 
them?  Keep  a  simple  shrub  calendar  showing  dates 
of  the  opening  of  leaf  and  flower  buds.  How  are 
shrubs  usually  propagated?  (See  Cuttings,  p.  263.) 

Make  a  list  of  native  shrubs  in  nearby  woods. 
How  many  of  these  do  you  find  on  home  or  school 
grounds  ? 

Notice  the  homes  in  your  district  and  decide  which 
ones  have  the  shrubs  arranged  most  artistically. 
How  many  of  the  rules  for  shrub  planting  do  you 
know  ? 

Discussion.  Shrubs,  more  than  any  other  plants, 
may  be  used  to  give  a  beautiful,  natural  setting  to  a 
home.  They  differ  from  trees  in  that  they  send  up 
a  number  of  stems  from  the  root  instead  of  one  main 
trunk.  They  never  grow  as  tall  as  trees  and  many  of 
the  most  beautiful  ones  have  drooping  branches.  In 
cool  climates  they  have  the  same  habit  as  trees  in 
preparing  for  the  winter  season;  that  is,  they  start 
their  buds  in  the  latter  part  of  the  summer,  cease  their 
work,  and  the  deciduous  ones  drop  their  leaves. 

Projects.     If  you  are  planning  to   set  out  shrubs 


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STUDIES  IN  SCIENCE 


on  home  or  school  grounds  you  must  know  not  only 
the  best  shrubs  to  use,  but  how  and  where  to  place 
them.  To  begin  with  you  should  observe  the  follow- 
ing general  rules:  1.  Leave  an  open  lawn  with  the 
shrubbery  grouped  at  the  sides  or  near  the  build- 
ings. 2.  Plant  to  give  mass  effect;  do  not  scatter 
the  shrubs.  3.  Avoid  straight  lines  except  in  the 
making  of  hedges.  4.  Put  together  colors  that  will 
harmonize,  or  plan  for  a  succession  of  flowers. 

With  the  consent  of  your  parents  draw  up  a  plan 
for  the  planting  of  your  home  grounds.  The  work 
need  not  be  completed  in  one  year.  Start  it  now  and 
continue  year  after  year  till  it  is  finished.  It  .is  very 
important  to  have  a  well  arranged  plan  before  you 
begin. 

SHRUB  TABLE 

The  date  of  flowering  is  given  for  regions  in  about  40°  north 
latitude.  N.  after  a  name  indicates  that  the  shrub  is  native  to  this 
country.  Shrubs  that  are  starred  are  especially  attractive  to  birds. 


Name 

Date  of 
flowering 

Color  of 
flower 

Color  of 
fruit 

Low  —  from  2  to  4  ft. 
*  Japanese  barberry  

June 

Pale  yellow 

Scarlet 

Berberis  Thunbergii 
Indian  currant  N  

June 

White 

Red 

Symphoricarpus  vulgaris 
Sweet  scented  sumac  N  
Rhus  aromatica 
Dwarf  spirea 
Spirea  Japonica 

July 
March-April 

Yellow 
White 

Dark  red 

LANDSCAPE  GARDENING 


461 


Name 

Date  of 
flowering 

Color  of 
flower 

Color  of 
fruit 

Early    spirea  

March-April 

White 

Spirea  arguta 
Low  hydrangea  N  

July 

White 

Hydrangea  arborescens 
New  Jersey  tea  N  

June 

White 

Black 

Ceanothus  Americanus 
Spice  bush  N 

May 

Dark  purple 

Calycanthus  floridus 
Low  deutzia                    .    .    . 

June 

White 

Deutzia  gracilis 
'Honeysuckle          

May 

White 

Red 

Diervilla  lonicera 

July-August 

Greenish 

Red 

Rhus  copalina 

Medium  —  from  5  to  7  ft. 
*High  bush  cranberry  N.  .  .  . 
Viburnum  opulus 
*Arrowwood  N 

May-June 
June 

White 
White 

Bright  red 

Viburnum  acerfolium 
Golden  bell 
Forsythia  intermedia 
*Honeysuckle    

March-April 
May-June 

Yellow 
White-yellow 

Lonicera  Morrowii 
Spirea    

May 

White 

Spirea  Van  Houttei 
Snow  berry  N  

June-July 

Pink 

White 

Symphoricarpus  racemosus  . 
White  kerria  

Mav 

White 

Rlarfr 

Rhodotypos  kerriodes 
Weigelia   

Mav-June 

Rose 

Weigelia  rosea 
*Flo\vering  currant  N  
Ribes  aureum 
Dogwood  N  

April-May 
May-June 

Yellow 
White 

Black 

Whitish 

Cornus  stolonifera 

462 


.STUDIES  IN  SCIENCE 


Name 

Date  of 
flowering 

Color  of 
flower 

Color  of 
fruit 

Hydrangea   *  

July-August 

White-rose 

Bronze 

Paniculata  grandiflora 
False   Indigo  N.   ,       ... 

May-June 

Blue 

Amorpho  fruticosa 
Privet  

June 

White 

Black 

Ligustum  amurense 
Privet    

June 

White 

Blue 

Ligustum  regels 

High—  from  7  to  12  ft 
*Elder  N  

July-  August 

White 

Black 

Sambucus  canadensis 
*Honeysuckle    

May-June 

Pink 

Red 

Lonicera  tartaria 
*Sumac    N  . 

June-Julv 

Red 

Red 

Rhus  typhina 
Button  bush  N  ,  .  .. 

May 

White 

:   Cephalanthus  occidental  is 
Japan  quince  

April-Mav 

Red 

Pyrus  japonica 
Mock  orange,  Svringa  

June 

White 

Philadelphus  coronarius 
Lilac 

April-Mav 

Lavender 

Syrihga  vulgaris 
Sweetbrier  rose  N 

June 

Pink 

Red 

Rosa  rubiginosa 
Prairie  rose  N  

June 

Pink 

Rosa  setigera 

...  »  ?  ,  ...  , 

rf  fcr.,.f.< 


'••jfco.'l^ 

You  have  such.  a  large  number  of  shrubs  from  which 
to  choose  that  you  may  find  it  difficult  to  decide  which 
ones  to  use.  As  far  as  possible,  select  those  that  are 
native  to  your  locality.  While  you  may  get  some  of 
them  directly  from  the  woods,  they  usually  give  better 


LANDSCAPE  GARDENING  463 

results  if  obtained  from  a  nursery  where  they  have 
been  grown  under  conditions  similar  to  those  of  your 
home  grounds.  From  your  study  of  cuttings  you 
know  that  if  you  are  willing  to  wait  a  year  or  two  for 
results,  you  may  start  many  of  you  own  shrubs. 

Border  planting.  In  order  to  carry  out  the  sug- 
gested rules,  plan  for  an  irregular  border  with  curved 
lines  along  the  sides  of  the  yard.  Do  not  make  the 
border  wide  enough  to  encroach  far  upon  the  open 
lawn.  Place  the  plants  close  enough  together  so  that, 
after  a  few  years,  the  individuals  will  be  obscured  in 
the  mass  effect.  Put  the  tall  shrubs  in  the  back- 
ground with  the  medium  and  low  in  front.  Consult 
the  Shrub  Table,  page  460.  If  the  yard  is  narrow,  it  is 
better  not  to  use  very  tall  plants  but  arrange  group- 
ings of  the  medium  and  low.  A  clump  in  the  corner 
running  back  to  a  few  near  the  fence  or  boundary  at 
the  middle  of  the  yard,  with  another  clump  extend- 
ing toward  the  building,  gives  a  very  pretty  effect 
for  a  small  yard. 

SUGGESTED  GROUPINGS  FOB  BORDERS 
(1,  2,  and  3  are  suitable  for  large  yards  only.) 

1.  Sumac,  typhina,  Dogwood,  and  Indian  currant 

2.  Elder  and  Forsythia 

3.  Japan  quince,  honeysuckle,  and  white  kerria 

4.  High  bush  cranberry,  snowberry,  and  Japanese  barberry 

5.  Spirea  Van  Houttei  and  dwarf  spirea 

6.  Spirea  Van  Houttei  and  Japanese  barberry 


464  STUDIES  IN  SCIENCE 

7.     In  clumps  by  themselves: 
Hydrangea 
Indian  currant 
Honeysuckle 
Snowberry 
Sumac,  Copalina 
Spice  bush 


Foundation  planting.  The  chief  purpose  in  plac- 
ing  shrubs  and  other  plants  close  to  the  house  is  to 
unite  the  building  and  the  grounds  so  that  they  will 
seem  to  belong  together.  The  plan  of  the  house 
should  be  studied  before  you  can  decide  where  to 
place  the  plants.  There  is  always  danger  of  using 
too  many  shrubs.  Mass  them  in  the  angles  of 
porches,  bay  windows,  and  steps.  Allow  the  clumps 
at  the  corners  to  extend  a  short  distance  along 
walks  or  form  irregular  screens  to  obscure  outbuild- 
ings. Plan  for  some  breaks  so  that  the  foundation  of 
the  house  will  here  and  there  be  directly  united  with 
the  grass  of  the  lawn.  Place  the  highest  shrubs  near 
the  buildings  with  the  lower  groups  next  to  the  lawn, 
Choose  those  whose  branches  droop  lightly  and  grace- 
fully over  the  grass. 

SUGGESTED  GROUPS  FOR  FOUNDATION 

1.  Spirea  Van  Houttei  and  Japanese  barberry 

2.  Honeysuckle,  Morrowii,  and  Deutzia  gracilis 

3.  Forsythia  intermedia  and  low  hydrangea 

4.  Indian  currant  and  Deutzia  gracilis 

5.  White  kerria  and  dwarf  spirea 


LANDSCAPE  GARDENING  465 

Buying  and  planting.  If  you  buy  shrubs  from  a 
nursery,  you  will  find  that  the  younger,  smaller 
plants  are  less  expensive  and  give  quite  as  satisfac- 
tory results  as  larger  ones. 

In  colder  portions  of  the  country,  shrubs  may  be 
set  out  either  in  the  spring  or  fall.  If  the  soil  is 
moist,  they  will  do  well  in  the  fall.  Spring  planting 
should  be  done  as  early  as  the  ground  can  be  worked. 
It  should  always  be  done  before  the  shrubs  have  put 
out  their  leaves. 

Eules  to  follow  in  planting: 

1.  After  the  plants  are  removed  from  the  nursery 
grounds,  keep  the  roots  well  covered  and  moist  till 
you  are  ready  to  set  them  out. 

2.  Dig  a  round  hole,  large  enough  so  that  the  roots 
may  be  spread  out,  and  deep  enough  so  that  the  plant 
may  be  set  a  little  farther  below  the  surface  than 
it  was  before  being  removed  from  the  ground. 

3.  Be  sure  that  the  soil  in  the  lower  part  of  the 
hole  is  rich  and  mellow.    It  is  sometimes  a  good  plan 
to  put  a  few  spadefuls  of  rich  soil  in  the  bottom  of 
the  hole. 

4.  Place  the  plant  in  the  hole  with  roots  spread 
out.    Put  in  a  few  spadefuls  of  earth,  then  firm  it  well 
about  the  roots.     This  is  usually  done  by  trampling 
with  the  feet.    Put  in  some  more  earth  and  firm  again. 
Continue  this  until  the  hole  is  filled.     The  last  three 


466  STUDIES  IN  SCIENCE 

or  four  inches  of  earth  need  not  be  firmed.  The  loose 
soil  will  help  to  conserve  the  moisture. 

5.  If  the  soil  is  dry  it  is  a  good  plan  to  pour  a  pail 
of  water  into  the  hole;  at  least  it  should  be 
thoroughly  watered.  If  the  soil  is  moist,  watering  is 
not  necessary. 

Care  of  shrubs.  Stir  the  soil  to  a  depth  of  several 
inches  two  or  three  times  during  the  first  two  years. 
After  that  once  a  year  is  sufficient.  Shrubs  require 
little  care.  They  should  be  allowed  to  grow  naturally, 
hence  they  need  little  pruning.  Severe  pruning  in 
the  spring  should  be  avoided.  If,  after  a  number  of 
years,  the  shrubs  are  too  thick  or  full,  it  is  better  to 
remove  one  or  two  bodily  from  the  clump  or  cut  out 
the  old  large  branches  so  you  will  not  spoil  the 
shape  of  the  shrubs.  For  a  number  of  years  it  is 
necessary  only  to  see  that  all  dead  wood  is  removed. 

Hedges.  While  the  irregular  border  gives  an  op- 
portunity for  greater  variety  and  more  artistic 
arrangement  of  plants,  yet  some  people  like  to  have 
their  grounds  enclosed  with  a  shrub  hedge  or  fence. 
Much  work  is  required  to  keep  such  a  hedge  in  good 
condition,  for  after  a  few  years  it  must  be  trimmed 
at  least  once  each  season,  usually  two  or  three 
times.  A  hedge  may  be  used  between  the  back  yard 
and  vegetable  garden,  even  if  the  border  planting 
is  used  in  front. 


LANDSCAPE  GARDENING  467 

Plants  for  hedges.  Deciduous:  Japanese  bar- 
berry, Berberis  Thunbergii,  common  barberry,  Amoor 
Eiver  privet,  California  privet.  This  last  winter  kills 
in  northern  and  north  central  states. 

Evergeen:  Arbor  vitae,  Norway  spruce. 

Shrubs  and  birds.  While  you  are  making  your 
home  and  school  surroundings  more  beautiful  by  the 
use  of  shrubs  and  vines,  you  may. at  the  same  time 
provide  a  home  for  wild  birds.  Many  birds  love  a 
shrub  thicket  in  which  to  nest.  By  choosing  shrubs 
that  produce  edible  berries  you  may  have  birds  com- 
ing to  feed,  not  only  during  the  summer,  but  far  into 
the  winter  months.  In  the  Shrub  Table,  page  460,  the 
ones  that  are  starred  are  especially  attractive  to  birds. 

2.     VINES 

Vines,  as  well  as  shrubs,  may  be  used  to  add 
beauty  to  the  home  and  its  surroundings.  Make  a 
study  of  the  vines  that  you  know.  Determine  how  they 
climb.  How  many  different  methods  of  climbing  do 
you  find?  Of  what  advantage  to  plants  is  the  climb- 
ing habit?  Classify  vines  as  to  their  length  of  life. 

If  you  look  closely  at  vines  you  find  that  some 
climb  by  twining  their  stems  around  supports.  The 
morning-glory  is  a  good  example  of  a  twiner.  Others 
climb  by  little  tendrils  or  roots  which  hold  fast  to 
the  support,  as  the  sweet-pea  or  Boston  Ivy.  Some 


468  STUDIES  IN  SCIENCE 

plants  with  tendrils  also  twine,  as  the  wild  grape. 
There  are  a  few  climbers,  chiefly  roses,  that  simply 
scramble  over  the  supports. 

Some  vines  are  annuals,  some  perenials.  Peren- 
nials are,  for  most  purposes,  more  satisfactory  than 
annuals.  Annuals  are  grown  largely  for  their 
flowers,  while  perennials  are  used  for  permanent 
screens  or  to  decorate  pillars,  porches,  and  even  the 
walls  of  buildings. 

Vines  may  be  used  to  advantage  on  any  home  or 
school  grounds.  You  may  use  them  to  cover 
unsightly  buildings,  as  old  woodsheds,  coal  houses, 
etc.  They  may  trail  over  the  back  fence  and  make  a 
background  for  a  flower  border.  They  add  both 
beauty  and  comfort  when  used  as  porch  screens.  In 
a  large  yard  a  rose  arbor  repays  in  pleasure  all 
the  work  and  effort  required  to  make  it  a  success. 

Some  of  the  most  satisfactory  perennials  are: 

Virginia  Creeper  or  Woodbine,  Ampelopsis  quinquefolia. 

Japanese,  or  Trumpet  creeper,  Teconia  radicans. 

Bitter  sweet,  Celastrus  scadens. 

Wild  grape,  Vitis  bicolor. 

Wild  clematis,  Clematis  Virginiana  and  paniculata. 

Wistaria,  Wistaria  siensis. 

Illinois  Rose,  Rosa  setigera. 

Dutchman's  pipe,  Aristolochia  macrophylla. 

Green  brier,  Smilax  rotundifolia. 

For  the  South: 

Yellow  Jessamine,  Geisemium  sempervirens. 
Malayan  Jessamine,  Trachelospermum  Jasminoides. 


LANDSCAPE  GARDENING  469 

Climbing  Asparagus,  Asparagus  plumosus. 

Kudzu  vine,  Pueraria  Thunbergiana. 

Cherokee  rose. 

Muscadine,   Vitis   rotundifolia. 

Annuals:  Sweet  pea,  tall  nasturtium,  cypress  vine,  morning-glory, 
moonflower,  cobea,  canary  bird  vine,  Balsam  pear,  wild  cucumber, 
scarlet  runner,  velvet  or  banana  bean. 

Very  pleasing  effects  are  gained  by  planting  a 
few  annuals  with  the  perennials,  and  allowing  them  to 
clamber  up  the  woody  stems  of  the  hardy  plants. 

In  planting  and  caring  for  perennial  vines  follow 
rules  suggested  for  shrubs. 

In  your  treatment  of  annuals  see  Planting  Table, 
p.  474. 

3.     PERENNIAL  FLOWERS 

Look  in  catalogs  for  lists  of  hardy  perennials  and 
decide  which  ones  you  would  like  to  grow.  Nothing 
can  give  you  more  pleasure  than  a  border  of  peren- 
nials in  your  flower  garden.  Some  of  them  may  be 
started  at  once  from  seeds  in  the  garden  border, 
although  they  probably  will  not  blossom  the  first 
year.  An  easy  way  to  start  perennials  is  to  arrange 
a  bed  of  rich  mellow  soil  in  a  sheltered  place  in  the 
garden,  and  sow  the  seeds,  placing  different  species 
in  rows  by  themselves.  When  the  seedlings  come  up, 
thin  them  until  they  stand  about  three  inches  apart. 
When  they  are  three  or  four  inches  high,  transplant 
them  to  their  permanent  places  in  the  border.  If  you 


470  STUDIES  IN  SCIENCE 

have  a  hotbed  or  green  house,  you  may  start  them 
very  early  and  get  quicker  results.  You  may  also 
sow  the  seeds  out-of-doors  in  the  latter  part  of  sum- 
mer, treating  the  seedlings  as  suggested  above.  In 
the  fall  cover  them  with  a  layer  of  leaves  or  straw. 
In  the  spring  they  will  be  ready  to  transplant  to 
their  permanent  places. 

Perennials  may  be  propagated  by  roots  or  under- 
ground stems,  as  well  as  by  seeds.  The  underground 
parts  are  dug  up  and  divided,  and  the  roots  set 
out  either  in  the  spring  or  fall.  People  who  have 
perennials  several  years  old  are  willing  to  divide 
their  plants  in  this  way.  In  some  cases  it  is  .an  ad- 
vantage to  the  plants  to  dig  them  up  and  separate 
the  accumulation  of  underground  parts. 

To  make  an  artistic  perennial  border  you  must 
know  the  height  of  the  plants  and  the  color  of  the 
flowers.  Group  the  plants  to  give  a  mass  effect.  Place 
tall  ones  in  the  rear,  with  clumps  of  medium  and 
low  in  front.  Mass  species  of  the  same  color 
together.  Use  low  plants  for  edgings. 

LIST  OF  PERENNIALS 

Tall,  from  5  to  8  feet:  Golden  glow,  Blackeyed  Susan  (Rudbeckia), 
Sunflower,  Helianthus  multiflorus,  Rudbeckia  purpurea,  Rudbeckia 
maximia,  Golden-rod,  Bocconia,  Hollyhock. 

Medium,  from  18  inches  to  4  feet:  Columbine,  Bleeding  heart, 
Peonies,  Hardy  Gaillardia,  Japan  Iris,  Oriental  Poppy,  Phlox,  Lark- 
spur, Cardinal  Flower,  Coreopsis,  Sweet  William,  Shasta  Daisy, 
Crimson-eye  Mallow,  Pyrethum,  Hardy  Chrysanthemum. 


LANDSCAPE  GARDENING  471 

Low,  6  to  12  inches:  Hardy  candy  tuft,  Forget-me-not,  Orna- 
mental grasses,  Low  iris,  Lily  of  the  Valley,  Meadow  rue,  Shoot- 
ing Star. 


4.     ANNUAL  FLOWEKS 

Material.    Seeds,  catalogs. 

First  look  in  your  seed  catalog  for  the  plants  that 
you  know,  then  for  others  that  you  think  you  would 
like  to  grow.  Consult  table  for  colors.  Do  not  choose 
many  unless  you  are  going  to  work  a  large  plot  of 
ground.  If  you  are  planning  to  sell  flowers,  choose 
those  that  are  most  likely  to  be  in  demand  and  that 
continue  to  blossom  for  some  time.  Sweet  peas,  pan- 
sies,  asters,  gladiolus,  dahlia,  tube  roses  all  sell  well. 

If  you  are  raising  your  flowers  for  home  use, 
choose  the  ones  that  the  family  like  best.  It  is, 
however,  always  worth  while  to  try  at  least  one 
new  species. 

SUGGESTED  GROUPS  FOB  PROJECTS 
(Those  that  are  starred  are  excellent  for  cut  flowers.) 

Name  Height  Color 

1.  Sweet   alyssum 9  in.         White 

*Cornflower  or  bachelor 

button    18  in.         Blue 

2.  Dwarf  Nasturtium 12  in.         Yellow  and  Orange 

*Gaillardia    15  to  18  in.         Yellow,  Orange,  Dark  Red 

3.  Verbena  6  to    9  in.         Mixed  colors 

*China    asters..  ..18  to  24  in.         Mixed  colors 


472  STUDIES  IN  SCIENCE 

(Those  that  are  starred  are  excellent  for  cut  flowers.) 


4.  *California   poppy... 

12  in. 

Yellow 

*Calendula   

15  in. 

Yellow 

5.     Pansies    

6  in. 

*Larkspur    

15  in. 

Blue 

6.     Portulaca    

6  in. 

Mixed  colors 

*Sweet  scabious  

15  in. 

Mixed  colors 

7.     Dwarf  marigold  

9  in. 

Shades  of  yellow 

Calliopsis    

15  in. 

Shades  of  yellow 

8.     Dwarf  coxcomb  

...  9  to  12  in. 

Purple-red 

Tall  coxcomb  

24  te  30  in. 

Purple-red 

9.     Ageratum    

...   6  to    9  in. 

Blue 

Corn  flower  

18  im. 

Blue 

10.     Sweet   alyssum  

9  in. 

White 

Browallia    

15  in. 

Blue 

The  following  are  prettier  if  planted  in  beds  by  themselves: 
Zinnia,  *Dahlia,  *Cosmos,  Gladiolus,  Poppies,  Balsam,  Pinks,  Pe- 
tunia, Salvia. 


If  you  are  going  to  succeed  with  your  flower 
projects,  you  must  know  something  of  the  habits 
of  the  plants  you  are  to  grow,  as  well  as  when,  where, 
and  how  to  plant  them.  Some  seeds  are  hardy 
enough  to  grow  in  cool  soil  and  the  plants  are  able 
to  stand  a  low  temperature,  even  a  slight  frost,  with- 
out injury.  Others  must  not  be  planted  until  the 
soil  is  warm  and  all  danger  of  frost  is  past.  Still 
others  in  northern  states  must  be  started  indoors  and 
transplanted  when  the  weather  is  warm. 


LANDSCAPE  GARDENING 


473 


PLANTING  TABLE — ANNUAL  FLOWERS 

The   numbers  indicate  height.     No.   1  from  6  to   9  inches,  No.   2,   10 
to  18  inches,  No.  3,  19  to  24  inches,  No.  4,  27  to  30  or  more  inches. 


Name                  Col 

Date  to  Plant 

£  cu  Distance  Inches 

S1"  In  Row 
Q£                 Of  Rows 

1  Ageratum,  blue,  white... 

Indoors,  Mr.  25  to  Apr.  5 
Garden,  May  10  to  15. 
April  1  to  15 

K 

% 

% 

% 

\ 

I 
I 
I 

\ 
V* 

% 
% 

8 

% 

l 

% 
% 
% 

i 
i 

it 

Vs 

% 

H 

% 

% 
% 
1 

% 

9 
9(3) 
9 

12 
12 
12 
9 
9 
12 
9 
9 
12 

9 
9 
18 

12 
9 
Hills 

12 
to 
15 
12 
2to4 
9 

9 

12 

12 
9 

6 

12 
& 

e 

6to9 
12 
12 

1 
12 

12 
9 
12 

15 
18 
18 
12 
18 
15 
12 
12 
12tol8 

18 
12 
24 

18 
15 
2  ft. 
apart 
Hedge 
or 
Clump 
18 
15 
18 

12 
18 

24 
12 

9 

18 
12 

12 
9  or  13 

18 
18 

36 

18 

Indoors,  Mar.  22  to  29. 
Garden,  May  5  to  12.  .  . 
May  8  to  12  ...  . 

3  Bachelor's  Button,  blue.. 
3  Balsam,   mixed,   red, 
white,    pink  

May  8  to  12.  . 

3  Blue  sage,  grayish,  blue. 

1  California  Poppy,  yellow 
2  Calliopsis,  orange,  yel... 
2  Calendula,  orange,  yel... 
1  Candytuft     white  

Indoors,  Mar.  25  to  31. 
Garden,  May  8  to  15 
April    20   to    25  
April  20  to  May  5 

April  20  to  May  5.  . 
April  15  to  30  
March  1  to  April  1. 
May  1  to  10  

2  Carnation    mixed        

4  Celosia,  purplish,  red.... 
1  Dwarf   Celosia,  purple,  r'd 

1  Chinese  pink,  red  &  pink 
3  Cosmos,    mixed  

*Indoors,   Mar.   25   to 
Apr     5  

"Indoors,   Mar.    21  to  25 
*Indoors,  March  25  to 
April    10 

—  Cypress  vine,  red,  white. 
2  Four   o'clock,   mixed  
3  Gaillardia,  mixed  

Garden,  May  1  to  15.. 
May  10  to  15  

April  10  to  20  

April  25  to  May  5 

—  Gourds  (vine)  white  

May  10  to  15 

4  Kochia,  deep  red  

Indoors,  April  1  to  15. 
Garden,  May  10  to  15. 

April  20  to  May  10  
April  20  to  May  10  
May  8  to  12  

3  Larkspur     mixed 

3  Linum,   blue  

2  Marigold  Tall,  brown,  red 
1  Marigold  Dwarf,  brown, 
red,  yellow  

May  8  to  12 

2  Mignonette,   yellowish, 
brown   

May  8  to  12 

4  Morning  Glory  vine, 
white,  red,   purple,  blue 
2  Nasturtium,   orange,   yel. 

1  Pansy,  purple,  white,  yel. 

2  Petunia,   purple,  white, 
pink  

April  15  to  20 

April  15  to  20  
Indoors,  Feb.  20  to  Mr.  1 
Garden,  May  10  to  15.  . 

2  Phlox,  mixed  

Indoors,  Mar.  15  to  20. 
Ga/den,  May  5  to  15.  .. 
Ap  'il  1  to  15 

2  Poppy,    mixed  

1  Portulaca,    mixed  

Api'il  20  to  30 

3  Salvia,  orange,  red 

Indoors,  Mar.  25  to  31. 
Garden,  May  5  to  15.  .. 
May  10 

3  Scabiosa,    mixed  

4  Scarlet   runner,    red   and 
white    

TVTfl  v  1  0 

2  Snap  dragon,  mixed  

Indoors,  Mar.  21  to  30. 
Garden,  May  10  to  15.  . 

*Plant  in  garden  May  10  to  15. 


474 


STUDIES  IN  SCIENCE 


Name                  Color 

Date   to   Plant 

£;  <u  Distance  Inches 

S'SJIn  Row 
5i3l               Of  Rows 

2  Stocks     mixed  

May    10  

% 
4to6 

K 
K 

% 

l 
H 

8 
15 
12 
3 
2 

12 
12 

12 
12 

12 
24 
18 
9 
24 

18 
18 

18 

Vine 
18 

4  Sunflower  (tall)  yellow.. 
3  Sunflower    (dwarf)    yel.  . 
1  Sweet  alyssum,   white.  .  . 
4  Sweet  peas    mixed 

May  10  to  15 

May  10  to  15  

April  1  to  10.  .    . 

April  1  to  10 

2  Sweet  William,    red   and 
white 

Feb    15  to  May  10 

1  Verbena,  mixed  

Indoors,  March  9  to  12 
Garden,  May  10  to  15. 
Indoors,  Max.  28  to  31. 
Garden,  May  10  to  15.  . 

In  Fall  or  Mar.  1  to  5  . 
May  8  to  12  

2  Vinca,   purple,   pink  and 
white    

4  Wild  cucumber  vine, 
white    

3  Zinnia,    mixed  

Where  to  plant.  The  best  place  for  your  annuals 
is  a  plot  in  or  near  the  vegetable  garden.  Do  not 
make  flower  beds  in  the  lawn.  If  you  have  not  begun 
to  plant  shrubs  around  the  foundation  of  the  house, 
you  may  find  a  spot  where  asters,  sweet  peas,  nastur- 
tiums, and  some  others  will  do  well,  but  this  is  not 
the  best  place  for  them.  Pansies  and  ferns  grow  well 
around  the  foundation  of  the  house. 

Successful  planting  includes: 

1.  A  careful  preparation  of  the  seed-bed.     The  soil 
should  be  fine  and  mellow. 

2.  In  most   cases  the   seeds   should  be  planted  in 
rows,  and,  if  in  beds,  they  should  be  elevated  slightly 
above  the  garden  level. 

3.  Do  not  plant  the  seeds  very  deep.    A  good  gen- 
eral rule  to  follow  is  to  plant  a  seed  to  the  depth 
of  four  times  its  diameter. 

4.  Firm  the  soil  well  over  the  seeds.     This  may  be 


LANDSCAPE  GARDENING  475 

done  with  the  back  of  the  hoe,  a  board,  or  by  step- 
ping upon  the  rows. 

5.  The   distance   between   the  rows   must  be   gov- 
erned by  the  size  of  the  plants.     See  Planting  Table. 

6.  If  you  use  annuals  for  borders  in  the  yard  or 
garden,    be    careful    to    plant    together    colors    that 
harmonize.   The  height   of   the   plants   must   also   be 
considered.     You  can  make  a  very  pretty  informal 
border  with  annuals,  if  you  are  not  ready  to  begin  the 
planting  of  shrubs  and  perennials.    Instead  of  shrubs 
use   castor  beans,  kochia,   cosmos,   tall   celosia,   and 
sunflowers. 


INDEX 


Air,  Composition  of,  385,  386,  387 

Diseases  in,  403 

Moisture  in,  405 

Pressure  of,  388,  390 
Alfalfa,  58 
Aphids,  208 
Apple,  The,  265 

Picking,   Storing  and  Market- 
ing, 268 

Study  of,  265 

Varieties  of,  267 
Asters,  28 

Bacteria,  239 
Barometer,  Uses  of,  389 
Bath,  The,  353 
Beans,  Study  of,  169 
Birds,  436 

Care  of,   447 

Enemies  of,  446 

Families  of,  440-444 

Groups  of,  438 

Lists  of,  450 

Part  of  a,  438 

Shore,  444 

Value  of,  445 
Blood,  Circulation  of,  399-401 

Composition  of,  499 
Blue-grass,  56 

Study  of,  453 
Braconids,  225 
Bread,  Making,  240 
Breathing,  Hygiene  o.f,  402 


Burdock,  72 
Butter,  294 
Butterfly,  The,  204 

Cabbage  Worm,  203 
Candle,  The,  325 

Power  of,  328 
Carbohydrates,  130 
Cattle,  283 

Breeds  of,  287,  290 

Care  of,  288 

Food  of,  288 

Housing,  291 

Value  of,  298 
Cellulose,  123 
Chickens,  421 

Breeds  of,  426 
Clinometer,  411 
Chlorophyll,  126,  127 
Clover,  58 

Clouds,  Forms  of,  414 
Clubs,  Boys  and  Girls,  147 
Cold  Frames,  145 
Combustion,  In  Air,  375 

In  Oxygen,  376 
Composites,  24,  28 
Conduction  of  Heat,  377 
Convection  Currents,  In  Air,  368, 
369 

In  Chimney,  370 

In  Wind,  371 
Cooking,  132 
Corn,  32 
476 


INDEX 


477 


Selecting    and     Storing    Seed 
Corn,  42 

Types  of,  44 
Cotton,  60 
Cow,  Beef,  286,  290 

Dairy,  285,  287 

Parts  of  a,  284 
Cow-peas,  38 
Crab-grass,  70 
Cucumber,  12,  165 
Cucumber  Beetles,  211 
Cucurbitacae,  13 
Cucurbits,  11,  165 
Cuttings,  Hard  Wood,  261 

Propagating  Plants  by,  255 

Soft  Wood,  261 

Dandelion,  71 
Digestion,  133 
Disinfectants,  251 
Disk  Flowers,  27 
Drainage,  105,  106,  107,  108 
Drupe,  A,  270 

Eating,  Hygiene  of,  135 
Evaporation  of  Liquids,  357,  358 
Eye,  The,  336 

Care  of,  337 

Parts  of,  336 

Farm  Crops,  32 
Fats,  131 
Feathers,  423 
Fertilizers,  118 
Fireless  Cooker,  377 
Flowering  Plants,  22 

List  of  Annuals,  471 

List  of  Perennials,  470 

Outline  of  Study  of,  23 

Parts  of,  22 


Planting  Table  for,  473 

Wild,  28 
Foods,  130 

Care  of,  137 

Classes  of,  130 
Forestry,  196 
Forests,  196 
Foxtail,  70 
Fruit,  265 
Fruit  Trees,  265,  272 

Care  of,  280 

Fuels,  How  They  Burn,  372 
Fungi,  228 

Bracket,  232 
Furnace,  Hot  Air,  366 

Garden,  The,  139 

Pests  of,  202 
Glaciers,  Work  of,  101 
Golden-rod,  28 
Gourd,  13 
Grafting,  274 

Cleft,  277 
Grasses,  52,  56 

Kinds  of,  452 

Health,  130 

Air  in  Relation  to,  395 

Bacteria  and,  250,  252 

Foods  and,  130 

Milk  in  Relation  to,  297 

Water  in  Relation  to,  346 
Heat,  364 

Conduction  of,  377 

Radiant,  379 

Regulation  of  in  Body,  361 
Heating,  364 
Hedges,  466 
Hogs,  309 

Breeds  of,  313 


478 


INDEX 


Care  of,  314 

Diseases  of,  316 

Food  of,  315 
Home  Projects,  139 

Beans  and  Peas,  169 

Calf,  298 

Colt,  309 

Corn,  176 

Cucumbers   and   Other   Cucur- 
bits, 165" 

Fruits,  282 

Lamb,  323 

Lawn,  457 

Oats,  183 

Onions,  160 

Pig,  317 

Potatoes,  155 

Poultry,  433 

Root  Crops,  152    > 

Shrubs,  460 

Tomatoes,  148 

Wheat,  187 
Horses,  299 

Care  of,  305 

Training,  308 

Types  of,  299 

Uses  of,  301 
Hotbed,  Making  a,  ,141 
House-fly,  218 
Humus,  96,  101 

Ice,  354 

Artificial,  360 
Ice  Cream,  Making,  383 
Ichneumons,  225 
Insects,  201 

Beneficial,  223 

List  of  Common  Pests,  221 

Poison  Sprays  for,  222 
Irrigation,  108 


Ladybird  Beetles,  224 
Lamp,  The  Gas,  332 

The  Kerosene,  329 
Landscape  Gardening,  451,  463 

Rules  of,  460 
Lawn,  The,  452,  456 
Leaves,  86,  91 

Parts  of  a,  87 
Legumes,  52,  56 
Light,  325 

Electric,  334 

In  Early  Times,  328 
Lighting,  325 
Lungs,  Structure  of,  399 

Meadow  Grasses,  53 

Melon,  13 

Milk,  Care  of,  295 

Composition  of,  291 

Separation  of,  292 

Testing,  296 
Mold,  233,  235 
Mosquitoes,  214  ^ 

Malaria  Transmitted  by,  217 
Mushroom,  228,  230 

Native  Woods,  195 

Oats,  183 
Onions,  160 

Oxidation  in  Body,  351 
Oxygen,  Behavior  of,  376 
How  to  Make,  374 


Parasite,  236 
Pasture  Grass,  53 
Peach,  The,  271 
Perennials,  27 
Petunia,  7 
Pigweed,  68,  70 


INDEX 


479 


Plants,  110 

Food  of,  112 

Propagating  by  Cuttings,  255 

Transpiration  of,  116 

Transplanting,  259 

Work  of,  120 
Pome,  A,  270 
Potatoes,  16 

Sweet,  19 
Poultry,  421 

Breeds  of,  426 

Care  of,  432 

Feeding,  431 

Housing  of,  428 
Proteids,  131 
Pruning,  281 
Puffballs,  229,  230 
Pumpkins,  13 
Pumps,  391 

Making  a,  392 

-adiant  Heat,  379 
Ray  Flowers,  27 
Refrigerator,  The,  382 
Respiration,  397 
Rotation  of  Crops,  117 

Seed-bed,  Preparing  the,  146 
Seed,  The  Making  of  a,  30 
Separation  of  Milk,  292 
Sewage,  Disposal  of,  349 
Sheep,  318 

Care  of,  321 

Types  of,  320 
Shrubs,  457 

Care  of,  466 

Rules  in  Planting,  460 

Table  of,  460 
Skin,  Care  of,  352 
Smartweed,  70 


Soils,  95 

Composition  of,  96 

Origin  of,  98 

Water  in,  103 
Soy-beans,  58 
Smuts,  235 
Spraying,  282 
Springs,  345 
Squash,  11 
Squash-bug,  207,  209 
Sun,  Observations  of,  409-413 
Sunflower,  25 
Swine,  309 

Breeds  of,  313 

Care  of,  314 

Teeth,  The,  136 
Temperature,  409 
Thermometer,  The,  379 
Thistle,  72 
Tillage,  116 
Timothy,  57 
Tissue,  Kinds  of,  350 
Toadstool,  228,  230 
Tomato,  8 

Canning  the,  150 
Tomato-worm,  206 
Transplanting,  259 
Trees,  84,  189 

Care  of,  199,  280 

Food  of,  194 

Fruit,  265,  272 

Outline  for  Study  of,  89 

Parts  of  a,  84 

Types  of,  90 

Uses  of,  197 
Twig,  88,  273 

Parts  of  a,  88,  192 

Vacuum  Cleaner,  The,  393 
Vapor,  Water,  356 


480 


INDEX 


Vegetables,  8 
Ventilation,  395,  396 
Vines,  467 

List  of,  468 
Vivarium,  A,  201 

Water,  103 

Capillary,  104,  113 
Evaporation  of,   357,  358,  362, 

363 

Ground,  103,  104 
How  to  Secure  Pure,  347 
Need  of,  350 
Source    of    Supply   in    School, 

339 


Weather,  406 

Map  of,  418,  419 

Record  of,  407,  408 
Weeds,  67 

Getting  Rid  of,  75 

List  of  Common,  77 

Outline  Record  for  Study  of,  67 
Wells,  342-344 
Wheat,  46 

Varieties  of,  49 
Winds,  417 
Wool,  322 


Yeast,  239 


/ 


YB  56827 


413117 


